Resin composition, packaging structure, and method for reproducing the same

ABSTRACT

A resion composition in which a coloring component comprising a polymer and having a regular configuration as a coloring principle is contained in a matrix resin, and a temperature at which the coloring component is decolored is higher than a temperature at which the matrix resin is processed. A packaging structure in which, on at least a portion of the surface of the packaging structure, portions which are different in optical characteristics from the surface are periodically arranged by use of a fibrous structure.

TECHNICAL FIELD

The present invention relates to a colored resin composition, apackaging structure, and a method for reproducing the packagingstructure. More particularly, it relates to a resin composition whichmaintains coloration when used as a packaging structure but can easilybe decolored by external stimulation during reproduction, a packagingstructure, and a method for reproducing the packaging structure.

BACKGROUND ART

Plastics are suitable for mass production owing to easy molding.Moreover, since the plastics possess excellent physical properties suchas transparency and impact resistance, they have been widely used asvarious kinds of packages such as bottle containers, cups, pouches, orpackaging sheets.

These packages are packed with various drinks, seasonings, cosmetics,drugs and the like as contents. However, some of these contents changein quality or deteriorate by a light, and therefore, for the purpose ofprotecting such contents from the light, the packages are colored insome cases. Furthermore, in order to differentiate commercial productsfrom other similar products by decorating the packages to impartbeauties thereto, the packages may be colored sometimes for the additionof the beauties to the packages.

In general, the plastic packages are colored by mixing a coloring agentsuch as a pigment or a dye with a plastic which is a main material ofthe packages. When the coloring agent is mixed, the packages absorb alight having a specific wavelength to cause color appearance.

The wavelength of the light absorbed by a substance depends on achemical structure of the substance, and therefore, in order to obtain aspecific color, it is necessary to use a specific chemical substance.

Typical examples of the packages which are colored by mixing thecoloring agents are as follows.

For example, there may be mentioned plastic containers colored green,blue, brown and the like by mixing various pigments or dyes with resins.According to such containers, it is inhibited that a light having aspecific wavelength absorbed by coloring components penetrate into thecontainers, and in consequence, there is imparted thereto the protectionof the contents that are apt to change in quality or to deteriorateowing to the light beam, i.e., a visible light barrier performance. Inaddition, the containers colored with a specific color can create aproduct image and can be differentiated from other products, so that itis possible for consumers to enhance buying inclination of the ownproducts.

In recent years, however, from the viewpoints of the saturation oflandfill sites and resource saving, the recycle of resins has beenpromoted, but it is difficult to reuse the colored packages. Inparticular, PET bottles [bottles formed by using PET (polyethyleneterephthalate) as a fundamental resin] are required to be colorless in acase where they are treated as materials to be reproduced.

Therefore, in the case of the PET bottles colored with coloring agentsconstituted of conventional chemical substances, it is difficult todecolor them, which makes their recycle severe. This problem is commonto the whole plastic packages, but the PET bottles are used in largequantities, and hence, this fact is a particularly serious problem.

As a measure to solve the problem, for example, the packages aredecorated by covering the packages with colored labels, and these labelsare then separated from the packages prior to their reproduction.

This method permits the recycle of the packages themselves, but it isnecessary to peel and separate the labels from the packages after theuse of them.

On the other hand, there are cases that coloration is conducted by not achemical coloring mechanism but a physical coloring mechanism in whichthe reflection or interference of a light is utilized.

For example, Japanese Patent No. 1037819 (pages 1 to 3) describespearl-decorated containers constituted of a resin layer containing amica-based or titanium-based pearl pigment and an opaque resin layerappearing a desired color which is disposed on the inner layer side ofthe resin layer.

According to such containers, a pearl decoration effect is obtained withthe aid of the pearl pigment, so that a high-quality appearance can becreated and also it is possible for consumers to enhance buyinginclination of the own products by differentiation from other products.

Furthermore, Japanese Patent Laid-Open No. 011369/1997 (pages 2 to 11)describes multilayer resin containers in which at least one layer ofmultilayer resins constituting the multilayer resin container is a resinlayer obtained by mixing an interference color pigment with athermoplastic resin.

According to such containers, the interference color pigment is mixedwith at least one layer of the multilayer resins, so that theproductivity of the containers can be improved. In addition, a materialcost can be decreased, and the expression of an interference color whichfinely changes depending on a view angle can beautifully be realized ina stereoscopic state.

Furthermore, Japanese Patent Laid-Open No. 80928/1996 proposes packages,in which a layer containing a scaly thin film having a high refractiveindex so as to be oriented in the direction of the surface of eachpackage is disposed on the outer side of a thermoplastic resin layer toappear a chromatic color.

In the above packages, however, a mica or titanium pigment or the likeis used in large quantities as the scaly thin film, and therefore, theseparation of the material is necessary prior to their recycle, whichmakes their recycle severe.

Therefore, the method of coloration by the above physical coloringmechanism is not allowed in a present recycle process either, as in themethod by the aforementioned chemical coloring mechanism.

As described above, in the present packages in which the chemical orphysical coloring mechanism is employed, the pigments or dyes blended inthe packages cannot be removed in the recycle process.

Therefore, there is a problem that the packages once colored cannot beremanufactured in the form of the transparent packages.

As shown in FIG. 8, a flow of the manufacture of the packages, e.g., thePET bottles to their recycle can be mainly classified into a manufactureprocess, a distribution process, and a collection/remanufacture process.

Namely, the PET bottles manufactured by blow molding injection-moldedpreforms to stretch and orientate them are filled with contents, sold(consumed), and then collected. The collected PET bottles are separatedfrom colored bottles, crushed, washed to separate impurities therefrom,and then reproduced in the form of flakes or pellets.

In such a flow of the manufacture and the recycle, the injection moldingand blow molding are conducted in the manufacture process, and meltextrusion is conducted in a re-pelletization step in acollection/remanufacture process. In these steps, stimulations of a hightemperature, a high pressure and the like are applied to the material.

However, even when passed through the steps in which such stimulationsare applied, the pigments or dyes still remain without the disappearanceof colors because of their high coloration stability. Namely, thepigments or dyes permanently maintain the coloration once they are mixedwith the PET.

Therefore, there arises a problem that the colored PET bottles cannot beused as starting materials for the PET bottles to be re-manufactured.

In view of such present situations, in Japan and in a field ofmanufacture/recycle of the PET bottles, the manufacture and distributionof the PET bottles which cannot be reused are restrained. In otherwords, the coloration of the PET bottles is prohibited in principle fromthe viewpoints of the improvement of a reuse ratio of the PET bottlesand the promotion of the recycle.

In Japan, it is mentioned as one item of material evaluation standardswhich are self-organized standards that the PET bottles should becolorless and transparent.

The material evaluation standards are guideposts established to evaluatewhether or not the PET bottles once manufactured are suitable for thereuse and remanufacture, and they are self-organized agreements in thefield of the manufacture/recycle of the PET bottles.

FIG. 9 shows a flow of a reuse suitability test (reuse suitabilityevaluation) of the PET bottles performed in accordance with the materialevaluation standards.

As shown in the drawing, the reuse suitability evaluation is performedfor each of reproduced flakes obtained by crushing trial bottles to beevaluated, reproduced pellets obtained by melt molding the reproducedflakes, injection molded plates obtained by injection molding thereproduced pellets, and fibers, bottles and sheets obtained by moldingthe reproduced pellets.

As evaluation items, there are mentioned “appearance, crush suitability”for the reproduced flakes, “IV, color tone, dry suitability” for thereproduced pellets, “appearance, haze, thermal properties” for theinjection molded plates, and “moldability, mechanical properties, colortone, haze, etc.” for the fibers, the bottles and the sheets.

Particularly, among these evaluation items, “the color tone” is theevaluation item which is investigated in a wide range including thereproduced pellets, fibers, bottles and sheets.

If the trial bottles are contaminated with a pigment or a dye, theyremain colored with the pigment or the like even at a stage where theyare processed into the reproduced pellets, and hence, they do notsatisfy the evaluation standards of “the color tone”. In addition, thecolor of the trial bottles still remains even at a stage where they areprocessed into the fibers, the bottles or the sheets, and therefore, theevaluation standards of “the color tone” are not satisfied herein,either.

As described above, the PET bottles mixed with the pigment or the dye donot satisfy the material evaluation standards, and for this reason, theycannot be used as starting materials for the reproduction. Therefore,the coloring of the PET bottles is voluntarily restrained in makers ofthe PET bottles.

As understood from the above, it is essential from the viewpoint ofrecycle promotion to evaluate the suitability of the PET bottles to bereused in accordance with the reuse suitability evaluation based on thematerial evaluation standards. On the other hand, it is also necessarythat “the color tone” is evaluated in the suitability test to reject thecolored PET bottles.

As mentioned above, however, the coloring of the containers molded asthe PET bottles for the purpose of providing functions such as a visiblelight barrier and a decoration has been desirable from variousviewpoints of preventing the change in quality and deterioration ofcontents therein, promoting the commercialization of new products,differentiating them from other products, promoting the sales of ownproducts, and the like.

In view of such situations, in the field of the manufacture/recycle ofthe PET bottles, it has been required to propose a technology ofproviding consumers with the PET bottles which conform to the evaluationitems of the reuse suitability evaluation and simultaneously havefunctions such as the visible light barrier and the decoration. In otherwords, there has been desired a technology which is capable of providingthe colored PET bottles in a distribution process and simultaneouslycapable of decoloring the PET bottles in a collection/remanufactureprocess.

The present invention has been developed in consideration of the abovecircumstances, and an object of the present invention is to provide aresin composition, a packaging structure and a method for reproductionwhich permits possessing functions such as the visible light barrier andthe decoration in the distribution process, satisfying the evaluationstandards of the reuse suitability evaluation in thecollection/remanufacture process, and improving of a reuse ratio of thepackaging structures to promote the recycle of them.

DISCLOSURE OF THE INVENTION

In order to achieve the object, a resin composition of the firstinvention according to the present application comprises a matrix resinincluding a coloring component which comprises a polymer and which has aregular configuration as a coloring principle. In the resin composition,a temperature at which the coloring component is decolored is set so asto be higher than a temperature at which the matrix resin is processed.

In a case where the resin composition is constituted as in the above,the coloring component can be decolored by melting the resin compositionat a temperature higher than the processing temperature of the matrixresin in the collection/remanufacture process to destroy the regularconfiguration of the polymer.

Furthermore, during the processing of containers, the matrix resin canbe processed at a temperature equal to or lower than the temperature atwhich the coloring component is decolored, whereby the coloringcomponent can be introduced thereinto while the colored configuration ismaintained. Therefore, in a distribution process, the containers can bebrought to the market in a state where the resin composition is coloredwith the coloring component.

In this specification, the matrix resin means a resin constituting acontinuous phase in the resin composition.

More specifically, for example, in a case where PET bottles containingthe resin composition of the present invention are formed, the PETbottles are processed in a flow of manufacture/recycle (FIG. 8) asfollows.

Since the PET bottles manufactured according to the manufacture processare colored with the coloring component, they can possess and exhibit inthe distribution process the functions of the visible light barrier andthe decoration by the coloration. Namely, in the distribution processwhich only requires the functions of the visible light barrier and thelike in the flow diagram shown in FIG. 8, the PET bottles can becolored.

In the collection/remanufacture process, the bottles can be decolored bycarrying out melt-extrusion at a temperature equal to or higher than thetemperature at which the coloring component is decolored. Therefore,even in a case where the reuse suitability evaluation is conducted forproducts remanufactured through the collection/remanufacture process,the standards of “color tone” can be satisfied.

As described above, the remanufactured products can satisfy theevaluation standards even in the reuse suitability evaluation of the PETbottles and simultaneously can possess the functions of the visiblelight barrier and the decoration.

In addition, since even the colored PET bottles satisfy the evaluationstandards of the reuse suitability evaluation, they can be recycled.

Accordingly, a reuse ratio of the manufactured PET bottles can beenhanced, which leads to the improvement of recycle properties.

In a resin composition which is another embodiment of the firstinvention, a melting point corresponding to a temperature at which acolor of one of a plurality of polymers disappears is higher than atemperature at which the matrix resin is processed, in a case where thecoloring component comprises the plurality of polymers.

According to the resin composition constituted as in the above, even ina case where the coloring component is constituted of the plurality ofpolymers, the regular configuration of the coloring component can bedestroyed and the coloring component can be decolored by melt-extrudingthe resin composition at a temperature higher than the melting pointcorresponding to the temperature at which the coloring component isdecolored, when among the respective melting points of the plurality ofpolymers, the melting point corresponding to the temperature at whichthe coloring component is decolored is higher than the temperature atwhich the matrix resin is processed.

Moreover, during the formation of the containers, the regularconfiguration of each coloring component is not destroyed in processingthe matrix resin at a temperature equal to or lower than the meltingpoint corresponding to the temperature at which the coloring componentis decolored. Therefore, the processed containers can be colored.

Furthermore, in a resin composition which is another embodiment of thefirst invention, the coloring component is a multilayer laminate of twoor more resins whose refractive indices are different from each other.

According to the thus constituted resin composition, the coloringcomponent can be colored by a physical coloring mechanism. Therefore,the coloring component can be incorporated in the resin composition tocolor the resin composition.

Moreover, a packaging structure which is another embodiment of the firstinvention uses any of the resin compositions mentioned above.

According to the thus constituted packaging structure, the coloringcomponent is incorporated in the matrix resin constituting the resincomposition, and a melting point (a temperature at which a colordisappears) of the coloring component is higher than a temperature atwhich the matrix resin is processed. In consequence, the resincomposition can be melt-extruded at a temperature higher than themelting point of the coloring component in the collection/remanufactureprocess, so that the remaining color of the packaging structure can beremoved.

Furthermore, in the manufacture process, the packaging structures isprocessed at the processing temperature of the matrix resin, so thatthese packaging structures can be colored.

Therefore, in the distribution process, the packaging structures canexhibit functions of the visible light barrier and the decoration.

In addition, as described above, the packaging structures can exhibitthe functions of the visible light barrier and the like in thedistribution process, and decoloration can be accomplished in thecollection/remanufacture process. In consequence, it becomes possible torecycle the packaging structures colored in the manufacture process.

Therefore, a reuse ratio of the packaging structures can be enhanced,which leads to the improvement of recycle properties.

Furthermore, a packaging structure which is another embodiment of thefirst invention has one or more layers comprising the resin compositionand one or more layers comprising a polyester.

According to the thus constituted packaging structure, it is possible toobtain a packaging structure in which the resin composition layer andthe polyester layer (e.g., a layer made of polyethylene terephthalate(PET) or the like) are laminated.

Moreover, according to a packaging structure of another embodiment, thematrix resin is a polyester.

According to the thus constituted packaging structure, most of the resincomposition layers are made of a polyester. Therefore, if the otherresin layers are also made of the polyester, the recycle of thepackaging structures can be further promoted.

Moreover, in a packaging structure of another embodiment, at least onepolymer of one or more polymers constituting the coloring component is apolyester.

According to the thus constituted packaging structure, the polyester iscontained in the coloring component, so that the polyester can also beused herein as in the matrix resin and the other resins, which leads tothe improvement of recycle properties.

Furthermore, in a packaging structure of another embodiment, the resincomposition is laminated by co-extrusion.

According to the thus constituted packaging structure, the resincomposition and PET can be laminated by, for example, co-extrusion.

In this case, a processing temperature of the matrix resin can be thesame as, for example, a set temperature of a flow path through which amelted resin is carried, or a set temperature of an extruder.

In a packaging structure of another embodiment, the resin composition islaminated by coating.

According to the thus constituted packaging structure, the laminationcan be effected by coating, for example, PET with the resin composition.

In this case, a processing temperature of the matrix resin can be setto, for example, a baking temperature.

A packaging structure which is the second invention is a packagingstructure having a configuration where on at least a portion of thesurface of the packaging structure, portions which are different inoptical characteristics from the above surface are periodically arrangedby use of fibrous structures. As such a packaging structure, there ismentioned, for example, a packaging structure in which the portionswhich are different in optical characteristics are portions which aredifferent in refractive index from the surface of the packagingstructure, or a packaging structure in which the portions which aredifferent in optical characteristics are voids formed inside the fibrousstructures.

Even such a packaging structure can be decolored by destroying theregular configuration of the fibrous structures by heating as in thecase of the first invention.

Moreover, a method for decorating the above packaging structure which isanother embodiment of the second invention is a method for decoratingthe packaging structure wherein the decoration is conducted by forming aconfiguration in which on at least a portion of the surface of thepackaging structure, portions which are different in opticalcharacteristics from the surface are periodically arranged by use offibrous structures. As various embodiments of such a decoration method,there is mentioned, for example, a method of the decoration by windingthe fibrous structures around a surface layer of the packagingstructure, a method of the decoration by mixing the fibrous structureswith a resin which forms the packaging structure, and a method fordecorating the packaging structure with a planar body obtained byprocessing the fibrous structures.

A packaging structure which is a third invention contains a colorationmaterial, but it is decolored or achromatized by external stimulationafter use.

As described above, in a case where the packaging structure isconstituted of the coloration material which can be achromatized by theexternal stimulation, the packaging structure can be colored with achromatic color which imparts a strong image to the feeling andmentality of a human in the distribution/use of the packagingstructures. In a remanufacture process after the use of the packagingstructure, the colored image of the packaging structure can beachromatized and weakened, whereby unnecessary coloration with thechromatic color to reproduced articles can be restrained.

Furthermore, in a case where the packaging structure is constituted ofthe coloration material which can be decolored by the externalstimulation, the packaging structure is obtained which is capable ofbecoming a colored state in the distribution/use of the packagingstructure. In a remanufacture stage after use, the packaging structurecan be completely decolored, which leads to the improvement of recycleproperties.

The above coloration material constituting the packaging structure ofthe present invention may have a coloring mechanism due to lightabsorption in a visual light region of the material.

Accordingly, a coloring mechanism of the coloration materialconstituting the packaging structure is due to the light absorption inthe visual light region of the material, and for example, its highcoloring ability permits effectively conducting the desired colorationof the packaging structure.

Moreover, the packaging structure of the present invention may take alaminated structure having a layer containing the coloration material.

As described above, in a case where the packaging structure is thelaminated structure having the layer containing the coloration material,the coloration material is kneaded with materials constituting layersother than the layer containing the coloration material in the packagingstructure and the other packaging structure, for example, in a meltkneading step of reproduction, whereby a surrounding environment of thecoloring component can be easily changed. Therefore, in a case of usingthe coloring component in which a color changes owing to the change ofthe surrounding environment, the packaging structure remains colored inthe distribution/use of the packaging structure, and in theremanufacture stage after use, the packaging structure can be decoloredor achromatized.

Furthermore, the packaging structure of the present invention can haveone or more layers comprising the coloration material and one or morelayers comprising a thermoplastic resin.

In a case where the packaging structure is made as in the above, it ispossible to constitute a packaging structure in which the layercomprising the coloration material and a polyester layer (e.g., a layermade of polyethylene terephthalate (PET) or the like) are laminated.

The above coloration material preferably comprises a resin as a mainmaterial. Furthermore, the main material resin of the layer comprisingthe coloration material is preferably the same kind of resin as thethermoplastic resin constituting at least one layer of other layerscomprising the thermoplastic resin.

The packaging structures containing the polyester resin as the mainmaterial, e.g., PET bottles are distributed in large quantities as drinkcontainers. In consequence, the present invention can be applied to thepackaging structures containing the polyester resin as the mainmaterial, whereby the PET bottles can easily be recycled, which caneffectively reduce environmental deterioration.

In the present invention, there is provided the packaging structure inwhich a chemical structure of at least one coloring componentconstituting the coloration material is changed by the externalstimulation to decolor or achromatize the packaging structure.

According to the coloring component made as in the above, a chromaticmaterial can be used in which there changes a light absorptionwavelength of the material in a visible light region by externalstimulation such as physical stimulation typified by heat, a light orchange in the surrounding environment. Consequently, in thedistribution/use of the packaging structure, it can remain colored, andin a remanufacture stage after use, the packaging structure can bedecolored or achromatized.

More specifically, the above external stimulation includes heat, a lightand change in the surrounding environment of the above coloringcomponent.

The change in the surrounding environment of the coloring componentincludes change in a hydrogen ion concentration, change in a polarity,change in a ligand concentration, change in a developer concentration,change in a surrounding resin, and the like.

The application of the external stimulation can change the chemicalstructure of the coloring component.

Moreover, in the present invention, a chroma difference (a²+b²)^(1/2)between a sheet molded using a resin obtained by reproducing thepackaging structure and an achromatic origin is set so as to be 5 orless. In a case where the chroma difference of the reproduced resin is 5or less, the resin can be evaluated as a colorless state in appearance,so that coloration of remanufactured products with an unnecessarychromatic color can be restrained.

It is to be noted that the evaluation is conducted by molding areproduced resin obtained by remanufacture into a sheet having athickness of 0.3 mm, placing a standard white board (X78.42, Y81.00,Z92.32) on the back of the sheet, and then measuring a Hunter Lab of thesheet by a reflection method.

A method of reproduction of packaging structures which is a forthinvention comprises collecting the packaging structures, melting them,and carrying out reproduction. In this case, the melting for thereproduction is conducted at a temperature equal to or higher than atemperature at which the coloring component contained in the packagingstructures is decolored.

In the above method of the reproduction of the packaging structures, thecollected packaging structures are molten at the temperature equal to orhigher than the temperature at which the coloring component isdecolored, whereby the regular configuration of the coloring componentcan be destroyed and consequently decolored. Accordingly, the packagingstructures can satisfy the reuse suitability evaluation in thecollection/remanufacture process.

According to the above method of the reproduction of the packagingstructures, the packaging structures can exhibit functions of a visiblelight barrier and a decoration in a case where the packaging structuresare filled with contents and supplied to consumers. Furthermore, in thecollection/remanufacture process, the packaging structures aredecolored, which makes their recycle possible. Therefore, a reuse ratioof containers and the like processed from the packaging structures canbe enhanced, and hence the promotion of their recycle can be expected.

Moreover, as another embodiment of the method of the reproduction, thereis a method in which external stimulation is applied to the packagingstructures in at least one step of a melting step, a dilution step andan alkali-washing step during reproduction of the packaging structuresto decolor or achromatize the packaging structures. It is preferablethat the application of the external stimulation is carried out in onestep of the melting step, the dilution step and the alkali-washing stepof the reproduction of the packaging structures.

For example, the coloration of a plastic packaging structure imparts abeauty to the packaging structure in order to differentiate commercialproducts from other similar products, and hence, the coloration plays animportant role for decoration. However, there is a problem that, in aproduction step, the colored packaging structure can be used only forproducts which will be colored in the same color, when molded articlesfor purge and defective products which are formed during the productionare utilized again as parts of starting materials for the products.

As described above, in at least one step of the melting step, thedilution step and the alkali-washing step during reproduction of thepackaging structures, the external stimulation is applied to thepackaging structures to decolor or achromatize them, whereby therestriction on color tone during remanufacture of colored moldedarticles is relieved, which can enhance productivity.

It is to be noted that a general product distribution cycle of PETbottles is shown in FIG. 8. More specifically, the manufactured PETbottles are filled with contents and then distributed to the market, andafterward, they are used and discarded by usual consumers. The discardedPET bottles are collected. Then, the bottles which cannot be recycledare separated, and the recyclable bottles are crushed and washed with anaqueous alkali (pH=10 to 14) (alkali washing step). After other resinsand impurities are removed by specific gravity separation orwind-powered separation, the bottles are flaked, melt kneaded (meltkneading step) if necessary, and re-pelletized to reproduce them.

The PET bottles are decolored by stimulation in the dilution step, thealkali washing step or the melt kneading step for the reproduction,whereby the colored packaging structures can be remanufactured withoutnew facilities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for illustrating a chemical coloring mechanism and aphysical coloring mechanism, and FIG. 1(a) shows the chemical coloringmechanism and FIG. 1(b) shows the physical coloring mechanism.

FIG. 2 is a phase diagram showing a constitution of a coloring componentcontained in a matrix resin.

FIG. 3 is a sectional view showing a constitution of the packagingstructure of the present invention.

FIG. 4 is a sectional view showing another constitution of the packagingstructure of the present invention.

FIG. 5 is a drawing showing a section cut in the diameter direction of afibrous structure used in the present invention, and FIG. 5(a) shows anexample of a divided side and FIG. 5(b) shows an example of anisland-sea type.

FIG. 6 is a drawing for illustrating a first embodiment of a decorationmethod of the present invention.

FIG. 7 is a drawing for illustrating a fourth embodiment of thedecoration method of the present invention.

FIG. 8 is an explanatory drawing showing a flow from manufacture torecycle of PET bottles (a flow of manufacture/recycle of PET bottles).

FIG. 9 is an explanatory drawing showing a flow of reuse suitabilityevaluation.

BEST MODE FOR CARRYING OUT THE INVENTION

The following will explain the present invention in detail.

In this specification, “coloration” and “decoration” have meaningsincluding coloration of a packaging structure with a chromatic color,block of a light having a specific wavelength region so that the lightmay not pass through the packaging structure, and the like.

First Invention: Resin Composition

A resin composition of the present invention is characterized in that acoloring component constituted of a polymer and having a regularconfiguration as a coloring principle is contained in a matrix resin,and a temperature at which the coloring component is decolored is higherthan a processing temperature of the matrix resin.

The coloring component is constituted of the polymer.

As the polymer, for example, a thermoplastic polyester can be used. Asthe thermoplastic polyester, there can be used an aliphatic, analicyclic or an aromatic polyester which is derived from a dicarboxyliccomponent and a diol component, or a copolymer or a blend thereof.Examples of the dicarboxylic acid component include aromaticdicarboxylic acids such as terephthalic acid, isophthalic acid andnaphthalenedicarboxylic acid; aliphatic carboxylic acids such assuccinic acid, adipic acid and sebacic acid; and alicyclic dicarboxylicacids such as cyclohexanedicarboxylic acid. Examples of the diolcomponent include aliphatic glycols such as ethylene glycol, diethyleneglycol and butanediol; alicyclic glycols such as cyclohexanedimethanol(CHDM); and aromatic diols such as bisphenols. Furthermore, polybasiccarboxylic acid components and polyhydric alcohol components having atrivalent or a higher valent functional group can also be used.

More specifically, polyethylene terephthalate (PET), polybutyleneterephthalate (PBT), polyethylene naphthalate (PEN), polycarbonates,polyarylates, isophthalic acid-copolymerized PET (PET-I),cyclohexanedimethanol (CHDM)-copolymerized PET, polyesters copolymerizedwith a soft segment constituting a polyolefin or a polyether, and thelike are suitably used.

Moreover, a thermoplastic polyamide can be used. As the thermoplasticpolyamide, there can be used an copolymers, polybutene-1,ethylene-butene-1 copolymers, propylene-butene-1 copolymers,ethylene-propylene-butene-1 copolymers, ethylene-vinyl acetatecopolymers, ionically crosslinked olefin copolymers (ionomers), andblends thereof. Additionally usable examples of the olefin resin includepolyacrylonitrile, polystyrene, polymethylpentene, polyvinyl alcohol,polymethyl methacrylate, cyclic olefinic copolymers (COC), andfluorinated polymers. Moreover, polymers capable of taking a cholestericliquid crystalline structure can be used. For example, celluloses suchas hydroxypropyl cellulose, and polypeptides such as polyglutamateesters can be mentioned. Furthermore, there can be used polymers inwhich the cholesteric liquid crystalline structure can be fixed byproviding a crosslinking reaction site in each molecule or including itin a curable matrix, and as such polymers, common curable resins can beemployed.

Additionally, at least one polymer of one or more polymers contained ascoloring components may be a polyester.

Typical examples of the polyester include polyethylene terephthalate(PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN),polycarbonates, polyarylates, isophthalic acid-copolymerized PET(PET-I), cyclohexanedimethanol (CHDM)-copolymerized PET, and polyesterscopolymerized with a soft segment constituting a polyolefin or apolyether. Since these polymers belong to the polyesters, the processingof the polyester resin into the matrix resin aliphatic, an alicyclic oran aromatic polyamide which is derived from a dicarboxylic component anda diamine component; a polyamide derived from an aminocarboxylic acid ora lactam thereof; or a copolymer or a blend thereof. Examples of thedicarboxylic component include aliphatic dicarboxylic acids such assuccinic acid, adipic acid, sebacic acid and decanedicarboxylic acid;and aromatic dicarboxylic acids such as terephthalic acid andisophthalic acid. Examples of the diamine component include linear andbranched aliphatic diamines such as 1,6-diaminohexane,1,8-diaminoocatane and 1,10-diaminodecane; alicyclic diamines such asbis(aminomethyl)cyclohexane and bis(4-aminocyclohexyl)methane; andaromatic diamines such as ω-xylylenediamine and p-xylylenediamine.Furthermore, examples of the aminocarboxylic acid include aliphaticaminocarboxylic acids such as ω-aminocaproic acid, ω-aminooctanoic acidand ω-aminoundecanoic acid; and aromatic aliphatic aminocarboxylic acidssuch as p-aminomethylbenzoic acid and p-aminophenylacetic acid.

More specifically, 6-nylon, 6,6-nylon, 11-nylon, 12-nylon, 6,10-nylon,6,12-nylon, MXD6 (m-xylyleneadipamide) nylon and the like are suitablyused.

Furthermore, an olefin resin can also be used as the polymer. Examplesof the olefin resin include polyethylenes (PE) such as low-densitypolyethylene (LDPE), medium-density polyethylene (MDPE), high-densitypolyethylene (HDPE), linear low-density polyethylene (LLDPE) and linearvery low-density polyethylene (LVLDPE); polypropylene (PP),ethylene-propylene or another layer can promote the recycle of the resincomposition.

Moreover, the coloring component has a regular configuration as acoloring principle. This means that the coloring component appears acolor by a physical coloring mechanism.

The coloring principle is classified into two kinds of chemical coloringand physical coloring.

As to the chemical coloring, when a white light including lights havinga plurality of wavelengths enters a material, coloring occurs owing toabsorption of a light in a wavelength range showing a specific color bythe material.

For example, as shown in FIG. 1(a), when the material absorbs a light ina wavelength range showing green color, lights of a reflected light anda transmitted light which enter eyes are observed as a red color whichis a complimentary color of the green color in both cases of the lights.

According to the principle of the chemical coloring, coloring occursowing to absorption of a light having a specific wavelength (a lighthaving a selected wavelength) by a substance with state energytransition of a chemical species.

The wavelength of the light absorbed by the substance depends on achemical structure of the substrate. Therefore, for the appearance of aspecific color, a specific chemical substance is required to be used.Examples of the specific chemical substance include a pigment and a dye.

On the other hand, as to the physical coloring, when the white lightenters the material, the coloring occurs owing to diffraction,interaction, scattering or the like of a light in a wavelength rangeshowing a specific color on the material.

For example, as shown in FIG. 1(b), when the material strongly reflectsa light in a wavelength range showing green color, the light whichenters eyes as a reflected light is observed as a green color. On thecontrary, a transmitted light is observed as a red color which is acomplimentary color of green color.

The coloring by this physical coloring mechanism is different from thecase of the chemical coloring mechanism, and the light is not emittedbased on properties inherent to the material but the coloring isachieved owing to formation of a certain configuration on an incidentplane of the light. Namely, the coloring occurs owing to the reflectionof the light having a specific wavelength (a light having a selectedwavelength) by diffraction or interference due to a regularconfiguration or a difference between refractive indices which thematerial has.

As characteristics of this physical coloring mechanism, the coloringoccurs so long as there is the regular configuration formation even inthe general-purpose material only, in contrast to the chemical coloringmechanism; decoloring is easily possible by the destruction of theregular configuration; and this mechanism is effective under a recycleregulation where usable materials tend to be limited.

Of these characteristics, a particularly important feature to accomplishthe present invention is that the decoloring can be easily made by thedestruction of the regular configuration.

When the coloring component is incorporated into the matrix resin, theresin composition containing the matrix resin is colored. Then, when thecoloring component is heated at a temperature equal to or higher than adecoloring temperature (a temperature at which the coloring component isdecolored), the regular configuration is destroyed to decolor it.

When this feature is utilized in a flow of manufacture/recycle of PETbottles, the following progress will be made.

In a manufacture process, when the coloring component is incorporatedinto the matrix resin, a PET bottle formed by laminating the resincomposition containing the matrix resin and a PET resin is colored.Then, in the collection/remanufacture process, when the coloringcomponent is heated, the regular configuration is destroyed to decolorit.

Therefore, in the distribution process in the flow of themanufacture/recycle of the PET bottles, the colored PET bottles can bebrought to the market. Thereafter, in the collection/remanufactureprocess, they can be decolored by heating or the like, so that theevaluation standards of “color tone” can be satisfied in the reusesuitability evaluation.

In consequence, the coloring component which appears the color by thephysical coloring mechanism is incorporated into the resin composition,and in the distribution process, the PET bottles can possess thefunctions of the visible light barrier and the decoration. Additionally,in the collection/remanufacture process, the evaluation standards of thereuse suitability evaluation are satisfied, and the remanufacture of thePET bottles becomes possible.

Examples of the configuration of the coloring component include a spiralconfiguration typified by cholesteric liquid crystals, and a laminateconfiguration.

As shown in FIG. 2(a), the cholesteric liquid crystals have a moleculararrangement of a spiral periodical configuration, and coloring occurs onthe basis of a reflection light due to the molecular arrangement.

When molecules are arranged in accordance with a spiral period=P, thereis selectively reflected only a light of a wavelength width Δλ=pΔn(Δn=anisotropy of a refractive index) around a wavelength λ=np (whereinn is an average refractive index of the liquid crystals) among lightsintroduced in parallel to a spiral axis, and lights within the otherwavelength range are transmitted.

The reflection by the cholesteric liquid crystals is more complex ascompared with a simple diffraction grating, because the reflection isdue to the spiral configuration. In counterclockwise cholesteric liquidcrystals, a light which satisfies wavelength conditions is divided intoa right circularly polarized light and a left circularly polarizedlight, and only the former is reflected and the latter is directlytransmitted. In clockwise cholesteric liquid crystals, reverse behavioroccurs. When an incident light has an incident angle θ, a light of awavelength which satisfies Bragg's reflection conditions of p·cos θ=λ/nis selectively reflected.

Moreover, the coloring component can be constituted of a multilayerlaminate of two or more resins having different refractive indices. Forexample, as shown in FIG. 2(b), in the laminate structure, two polymers,polymer A12-1 and polymer B12-2, having different refractive indices arelaminated. The laminate of the two polymers, polymer A12-1 and polymerB12-2, can be formed by, for example, co-extrusion.

Since the coloring component is constituted as in the above, coloringcan be effected by a physical coloring principle, and in addition,decoloring can be effected by destroying a regular configuration of themultilayer laminate constituting the coloring component.

Furthermore, when the coloring component is constituted of a pluralityof polymers, a melting point corresponding to a temperature at whichdecoloring occurs among melting points of the plurality of polymers isset to be higher than a processing temperature of the matrix resin.

Usually, when the coloring component is constituted of the plurality ofpolymers, these polymers have mutually different melting points. Thedecoloring of the coloring component occurs owing to destruction of theregular configuration which is brought about by melting at least onepolymer of the plurality of polymers.

Therefore, in a case where the plurality of polymers constituting thecoloring component have, for example, melting points of 250° C., 260° C.and 270° C., respectively, and when the destruction of the regularconfiguration finally occurs by heating the coloring component at 260°C. to effect the decoloring, a temperature of 260° C. is a discoloringtemperature of the coloring component and neither 250° C. nor 270° C. isthe discoloring temperature of the coloring component.

As described above, in the manufacture process, the resin compositioncan be colored by molding it at a temperature equal to or lower than atemperature at which the coloring component is decolored (e.g., 200°C.). In the collection/remanufacture process, the resin composition canbe decolored by melt extrusion or the like at a temperature equal to orhigher than a temperature at which the coloring component is decolored(e.g., 260° C.).

Furthermore, the coloring component is incorporated in the matrix resin.

Since the coloring component is incorporated in the matrix resin, theresin composition having a matrix resin layer can be colored.

As the matrix resin, for example, a thermoplastic polyester can be used.As the thermoplastic polyester, there can be used an aliphatic, analicyclic or an aromatic polyester which is derived from a dicarboxyliccomponent and a diol component, or a copolymer or a blend thereof.Examples of the dicarboxylic component include aromatic dicarboxylicacids such as terephthalic acid, isophthalic acid andnaphthalenedicarboxylic acid; aliphatic carboxylic acids such assuccinic acid, adipic acid and sebacic acid; and alicyclic dicarboxylicacids such as cyclohexanedicarboxylic acid. Examples of the diolcomponent include aliphatic glycols such as ethylene glycol, diethyleneglycol and butanediol; alicyclic glycols such as cyclohexanedimethanol(CHDM); and aromatic diols such as bisphenols. Furthermore, polybasiccarboxylic acid components and polyhydric alcohol components having atrivalent or a higher valent functional group can also be used.

Suitably usable typical examples of the matrix resin includepolyethylene terephthalate (PET), polybutylene terephthalate (PBT),polyethylene naphthalate (PEN), polycarbonates, polyarylates,isophthalic acid-copolymerized PET (PET-I), cyclohexanedimethanol(CHDM)-copolymerized PET, and polyesters copolymerized with a softsegment constituting a polyolefin or a polyether.

Moreover, a thermoplastic polyamide can be used as the matrix resin. Asthe thermoplastic polyamide, there can be used an aliphatic, analicyclic or an aromatic polyamide derived from a dicarboxylic componentand a diamine component; a polyamide derived from an aminocarboxylicacid or a lactam thereof; or a copolymer or a blend thereof. Examples ofthe dicarboxylic component include aliphatic dicarboxylic acids such assuccinic acid, adipic acid, sebacic acid and decanedicarboxylic acid;and aromatic dicarboxylic acids such as terephthalic acid andisophthalic acid. Examples of the diamine component include linear orbranched aliphatic diamines such as 1,6-diaminohexane,1,8-diaminoocatane and 1,10-diaminodecane; alicyclic diamines such asbis(aminomethyl)cyclohexane and bis(4-aminocyclohexyl)methane; andaromatic diamines such as m-xylylenediamine and p-xylylenediamine.Furthermore, examples of the aminocarboxylic acid include aliphaticaminocarboxylic acids such as ω-aminocaproic acid, ω-aminooctanoic acidand ω-aminoundecanoic acid; and aromatic aliphatic aminocarboxylic acidssuch as p-aminomethylbenzoic acid an p-aminophenylacetic acid.

More specifically, 6-nylon, 6,6-nylon, 11-nylon, 12-nylon, 6,10-nylon,6,12-nylon, MXD6 (m-xylyleneadipamide) nylon and the like are suitablyused.

Furthermore, an olefin resin can also be used as the matrix resin.Examples of the olefin resin include polyethylenes (PE) such aslow-density polyethylene (LDPE), medium-density polyethylene (MDPE),high-density polyethylene (HDPE), linear low-density polyethylene(LLDPE) and linear very low-density polyethylene (LVLDPE); polypropylene(PP), ethylene-propylene copolymers, polybutene-1, ethylene-butene-1copolymers, propylene-butene-1 copolymers, ethylene-propylene-butene-1copolymers, ethylene-vinyl acetate copolymers, ionically crosslinkedolefin copolymers (ionomers), and blends thereof. In addition thereto,there can be used polyacrylonitrile, polystyrene, polymethylpentene,polyvinyl alcohol, polymethyl methacrylate, cyclic olefinic copolymers(COC), and fluorinated polymers.

Of the above polymers, particularly suitable resins as the matrix resinconstituting the resin composition of the present invention arepolyethylene terephthalate (PET), polybutylene terephthalate (PBT),polyethylene naphthalate (PEN), polycarbonates, polyarylates,isophthalic acid-copolymerized PET (PET-I), cyclohexanedimethanol(CHDM)-copolymerized PET, and polyesters copolymerized with a softsegment constituting a polyolefin or a polyether. In view of the factthat these resins belong to polyesters, if the polyester resin isselected as a resin which is laminated together with the matrix resin,the recycle properties of the packaging structures can be enhanced.

Moreover, a processing temperature of the matrix resin is set so as tobe lower than a temperature at which the coloring component is decolored(decoloring temperature).

For example, when the decoloring temperature of the coloring componentis 270° C., it is suitable to use the matrix resin having a processingtemperature of about 200° C.

When such a temperature is set, the following effects are obtained inthe flow of the manufacture/recycle of the resin composition (packagingstructures, especially PET bottles).

In a manufacture process, when multilayer packaging structures of a PETresin and a resin composition are processed, for example, by adjusting aset temperature of a flow path introducing a melted resin inco-injection molding or a set temperature of an extruder to 200° C., thecoloring component is not destroyed. In consequence, the PET bottles canbe colored and distributed in the market in a colored state. Thereafter,in the collection/remanufacture process, when a step such as meltextrusion is conducted at a high temperature of 270° C. or higher, thecoloring component can be destroyed to effect decoloring.

Therefore, in the distribution process, the PET bottles to whichfunctions of a visible light barrier and the like are imparted by thecoloration can be provided for consumers. In thecollection/remanufacture process, the decoloring is effected, so thatthe reuse suitability evaluation is satisfied. Accordingly, thereutilization of the colored PET bottles is possible.

The resin composition of the present invention can be blended with knownadditives for the resin such as a filler, a colorant, a heat-resistantstabilizer, a light-resistant stabilizer, an antioxidant, an antiagingagent, a light stabilizer, a UV absorber, an antistatic agent, alubricant such as a metal soap or a wax, a resin for modification and arubber in accordance with a known prescription.

When the resin composition is blended with, for example, the lubricant,it is possible to reduce a load to the resin composition due to shearingduring melt processing and to improve inroads of a resin into a screw ofan extruder.

It is to be noted that the resin composition of the present invention isdesirably molded as one or more layers of a plurality of layers that thelaminate has.

The resin composition and the laminate can be used as packagingmaterials of films and sheets, and additionally, as packaging materialsof cups, trays, bottles and tube containers.

Packaging Structure

Typical examples of a packaging structure which is another embodiment ofthe first invention include packages such as films and sheets, andcontainers such as cups, trays and bottles. However, these packagingstructures use the above resin composition and contain at least onelayer comprising the resin composition (hereinafter referred to as“coloration layer”).

Therefore, the packaging structure is colored with the coloringcomponent incorporated in the coloration layer. Moreover, the coloringcomponent is decolored at a temperature (decoloring temperature) higherthan a processing temperature of the matrix resin which is thecoloration layer. Therefore, the packaging structure can be colored inthe manufacture process, and in the distribution process, the thuscolored packaging structure can be filled with contents and then broughtto the market. In the collection/remanufacture process, the packagingstructure can be melted at the decoloring temperature and hencedecolored, whereby the packaging structure becomes reusable.

However, the packaging structure can be processed with the resincomposition alone. Moreover, it can also be processed by laminating thecoloration layer and a layer constituted of one or more other resins.

The resin layer other than the coloration layer constituting thepackaging structure can be suitably selected from thermoplastic resinsand thermosetting resins, depending on a use manner, required functionsand the like.

Examples of the resin to be selected include mentioned olefin resins,thermoplastic polyester resins, and barrier resins.

Examples of the olefin resins include low-density polyethylene (LDPE),medium-density polyethylene (MDPE), high-density polyethylene (HDPE),linear low-density polyethylene (LLDPE), linear very low-densitypolyethylene (LVLDPE), polypropylene (PP), ethylene-propylenecopolymers, polybutene-1, ethylene-butene-1 copolymers,propylene-butene-1 copolymers, ethylene-propylene-butene-1 copolymers,ethylene-vinyl acetate copolymers, ionically crosslinked olefincopolymers (ionomers), and blends thereof.

On the other hand, examples of the thermoplastic polyester resinsinclude polyethylene terephthalate (PET), polybutylene terephthalate(PBT), polyethylene naphthalate (PEN), polycarbonates, polyarylates,isophthalic acid-copolymerized PET (PET-I), cyclohexanedimethanol(CHDM)-copolymerized PET, and polyesters copolymerized with a softsegment constituting a polyolefin or a polyether.

Moreover, examples of the barrier resins include ethylene-vinyl alcoholcopolymers (EVOH), cyclic olefinic copolymers (COC), especiallycopolymers of ethylene with cyclic olefins (APEL manufactured by MitsuiChemicals, Inc., etc.), and m-xylyleneadipamide (MXD6).

Between the respective resin layers, an adhesive resin can also beinterposed, if necessary. As such an adhesive resin, there can bementioned thermoplastic resins each having in a main chain or a sidechain a carbonyl group based on a carboxylic acid, a carboxylicanhydride, a carboxylate salt, a carbamide or a carboxylate ester. Asuitable example of the adhesive resin is one or a combination of two ormore of ethylene-acrylic acid copolymers, ionically crosslinked olefincopolymers, maleic anhydride-grafted polyethylene, maleicanhydride-grafted polypropylene, acrylic acid-grafted polyolefins,ethylene-vinyl acetate copolymers, copolymerized polyesters, andcopolymerized polyamides.

However, it is particularly preferable that the resin layer other thanthe coloration layer constituting the packaging structure is a layermade of the polyester resin.

When the resin layer other than the coloration layer is the layer madeof the polyester resin and if the matrix resin of the coloration layeris the polyester-based resin, the recycle properties of the packagingstructure can be enhanced. Moreover, when a part or all of the pluralityof polymers constituting the coloring component are made of thepolyester-based resin, the recycle properties of the packaging structurecan be further enhanced.

The laminated packaging structure is shown in FIG. 3. As shown in thesame drawing, the packaging structure can be processed by laminating acoloration layer (a layer made of a matrix resin 11 containing acoloring component 12) 10 and another resin layer 20.

In the same drawing, the packaging structure has one layer of thecoloration layer 10 and one layer of the other resin layer 20, but eachlayer is not limited to one layer. For example, as shown in FIG. 4, oneor both of the other layer 20 and the coloration layer 10 may have twoor more layers.

The coloration layer of the packaging structure can be laminated byco-extrusion processing.

The co-extrusion processing is a method of forming a laminate structureby plasticizing a plurality of melted resins separately, guiding themthrough a predetermined melted resin flow path, and joining them in amultilayer die or a nozzle. The following shows examples of theco-extrusion processing.

The packaging structure, e.g., a multilayer film, sheet or tube can beprocessed by extruding resins into a predetermined form through amultiple multilayer T-die, a circular die (ring die) and the like byusing as many extruders as the kinds of resins. The film processedthrough the T-die is biaxially stretched to form a biaxially stretchedfilm. Moreover, the multilayer film or sheet can also be obtained by anextrusion-coating method, a sandwich lamination method, or a drylamination of pre-processed films.

These films or sheets can be subjected to means such as vacuum forming,pneumatic forming, bulging or plug-assist forming to obtain, e.g.,cup-like or tray-like containers.

Moreover, the formation of a multilayer bottle from a parison, a pipe ora preform can be easily carried out by extruding it into a predeterminedform through a multiple multilayer die by using as many extruders as thekinds of resins, pinching it off with a pair of split molds, and blowinga fluid into it.

Furthermore, a multilayer preform which is a precursor for themultilayer bottle can be molded by use of a co-injection molding method.For the formation of the multilayer preform, there can be used as manyplasticizing apparatuses as the kinds of resins, a molding machineequipped with hot runners for guiding the melted resins into a mold, anda simultaneous injection method, a sequential injection method oranother method. Moreover, a co-compression molding method can also beused. The multilayer preform can be molded by extruding the resins intothe form of predetermined resin masses through a multiple multilayer dieby use of as many extruders as the kinds of resins, and then compressionmolding them with a mold.

The preform is adjusted or heated to a stretchable temperature whileheat at the preform molding is maintained or after the molded preform iscooled. Afterward, the preform is stretched mechanically in an axialdirection by a stretch rod in a product mold whose temperature isadjusted to a predetermined temperature, and blow-stretched in acircumferential direction by a fluid pressure, whereby a stretched blowbottle can be molded.

The coloration layer of the packaging structure can be laminated bycoating.

The coating lamination can be carried out by first dispersing thecoloring component in a curable base material, using an additive such asa solvent and a dispersant if necessary to prepare a coating material,applying the coating material onto the surface of the other resin layerby a known way such as gravure coating, spray coating or dip coating,and then curing it by means of heating or UV irradiation to form acoating film thereon.

This technique can also be used to obtain the packaging structure inwhich the coloration layer and the other resin layers are laminated.

Second Invention: Packaging Structure

A packaging structure of the second invention is decorated by applying aphysical coloring mechanism. Namely, a fibrous structure is used on atleast a portion of the surface of the packaging structure to form aconfiguration where portions which are different in opticalcharacteristics from the surface are periodically arranged, whereby alight is interfered/diffracted to effect coloring.

The “at least a portion” of the packaging structure means a portion orall of the package.

The “surface” of the packaging structure means a front side of thesurface forming the package or a section in the surface. Namely, thedecoration by use of the fibrous structure includes a case of thedecoration by arranging the fibrous structure on the surface forming thepackage, and a case of the decoration by packaging structure, the lightis refracted and interfered to effect the coloring.

FIG. 5(b) shows an example of an island-sea type fibrous structure 31 b,where its section has a configuration that the plurality of very finefibers are contained as island portions 35 in a fiber outer periphery(sea portion 34). Since the optical characteristics of the very finefibers constituting the island portions 35 or the sea portion 34 aredifferent from those of the surface of the packaging structure, thelight is refracted and interfered to effect the coloring.

In order to form the configuration that the portions which are differentin optical characteristics are periodically arranged, a resin which isdifferent in, e.g., the refractive index from the surface of thepackaging structure is used as the fibrous structure. For example, inFIG. 5(b), the sea portion 34 may be made of the same resin as the mainmaterial resin of the packaging structure, and the island portions 35may be made of a resin which is different in the refractive index fromthe main material resin of the packaging structure. As the resin for theisland portions, there can be considered combinations of thermoplasticpolyesters such as polyethylene terephthalate (PET), polyethyleneisophthalate, polybutylene terephthalate, polyethylene naphthalate,polycarbonates, polyarylates, copolymers of monomers forming the aboveresins and copolymers of cyclohexanedimethanol with monomers forming theabove resins, polyethylene (PE), polypropylene (PP), polystyrene, cyclicolefinic copolymers, ethylene-vinyl incorporating the fibrous structureinto a wall portion of the package.

The “main material resin” of the packaging structure means a resinforming the respective portions of the packaging structure, e.g., innerand outer layers, an intermediate layer and an adhesive layer. Namely,it contains a resin supporting the strength of the packaging structure,a functional resin having functions of gas barrier properties, moisturebarrier properties, gas absorbing properties, light controllingproperties and the like, an adhesive resin having a function for bondingthe respective layers of the multilayer package, and another resin.

The fibrous structure to be used in the present invention has portionswhich are different in optical characteristics from the main materialresin of the packaging structure. The optical characteristics include,for example, refractive index, reflectance, transmittance, absorbance,and polarization degree.

As the fibrous structure, there can be used, for example, a very finefiber, a fiber having voids therein, or a composite fiber made of anon-compatible resin of an island-sea structure.

In FIG. 5, as examples of the fibrous structure, sections in a diameterdirection are shown.

FIG. 5(a) shows an example of a divided type fibrous structure 31 a,where its section is constituted of fan blade-shaped portions 32 andsubstantially linear portions 33. Since the optical characteristics ofthese portions are different from those of the surface of the alcoholcopolymers, nylon resins, vinyl chloride resins, adhesive resins,polyamide resins, various engineering plastics such as polyimides, andcarbon nanotubes.

Moreover, it is also possible to change the refractive index by formingthe island portions 35 as the voids and forming the sea portion 34 froma resin. In this case, the refractive index of the voids shows the samevalue (about 1.0) as that of air, which is different from the refractiveindex of the resin portion (about 1.3 to about 1.5).

The periodical arrangement configuration formed by the fibrous structuredepends on a wavelength of a color which should be appeared or a lightwhich should be blocked. For example, in the case of the fibrousstructure having the island-sea section as shown in FIG. 5(b), thediameter of the island portion is properly in a range of 0.1 μm to 5 μmin order to block lights from UV region to IR ray. Moreover, when anarrangement period which acts on lights having wavelengths of 0.4 μm to0.7 μm in a visible light region is formed, the coloring of an optionalcolor is possible.

The diameter of the fibrous structure is preferably from 0.1 μm to 200μm from the viewpoints of a decoration effect and manufacture.

A periodicity of the periodical arrangement configuration formed by useof the fibrous structure is not necessarily complete. Defects such aspartial disappearance or unevenness of the periodicity anddiscontinuation of the periodical configuration are allowable, as longas the periodicity is maintained as a whole.

For manufacturing the fibrous structure, for example, a method formanufacturing the very fine fibers can be applied. The process formanufacturing the very fine fibers usually contains a step of extrudinga resin for the sea portion and a resin for the island portionsseparately through a multilayer die. A shape of the island portions, afiber diameter and a arrangement state are controlled by a nozzle shapeof an extrusion die for the island portions. Suitable determination ofthe nozzle shape permits manufacturing the very fine fibers having theperiodical arrangement configuration.

Subsequently, a method of decorating the packaging structure byutilization of the above fibrous structure will be described inaccordance with an example in which the method is applied to plasticbottle containers.

The plastic bottle containers can be molded by molding means of theusual bottle containers. For example, they can be obtained by subjectingpreforms to stretching blow molding.

As plastic materials which are used to form the plastic bottlecontainers, for example, preferable are thermoplastic polyesters such aspolyethylene terephthalate (PET), polyethylene isophthalate,polybutylene terephthalate, polyethylene naphthalate, polycarbonates,polyarylates, copolymers of monomers forming the above resins andcopolymers of cyclohexanedimethanol with monomers forming the aboveresins, polyethylene (PE), polypropylene (PP), polystyrene, cyclicolefinic copolymers, ethylene-vinyl alcohol copolymers, nylon resins,vinyl chloride resins, adhesive resins, blends of these resins, andblends of these resins with other resins. Particularly, ethyleneterephthalate-based thermoplastic polyesters such as polyethyleneterephthalate are preferable.

First Embodiment

FIG. 6 is a drawing for explaining a first embodiment of a decorationmethod using a fibrous structure.

In this embodiment, a plastic bottle container is decorated by windingthe fibrous structure around the plastic bottle container.

In FIG. 6, a fibrous structure 42 is wound around a body portion 41 of aplastic bottle container 40. In a postion on which the fibrous structure42 is wound, a phenomenon such as interference or reflection of a lightoccurs due to an optical periodical configuration formed by the fibrousstructure, so that the plastic bottle container is decorated.

For example, in a case where very fine fibers of an island-sea structureshown in FIG. 5(b) is used as the fibrous structure, there is obtained aconstitution that the very fine fibers constituting the island portionsare wound around the body portion 41 in a circumferential direction atregular intervals. In consequence, a periodical arrangementconfiguration of the sea portions and the island portions is formed.

At this time, when the sea portions are made of the same material as themain material resin of the plastic bottle container 40 and the fibrousstructure 42 is fused to the bottle container 40 by heating, the bodyportion 41 and the fibrous structure 42 can be integrated.

Second Embodiment

In this embodiment, a fibrous structure or an article obtained byprocessing the fibrous structure into a planar body is mixed with a mainresin of a plastic bottle container, so that portions having differentoptical characteristics contained in the fibrous structure areperiodically arranged on the surface of the container to decorate thecontainer.

The article obtained by processing the fibrous structure into the planarbody is, for example, a nonwoven fabric or a textile.

The fibrous structure or the article obtained by processing the fibrousstructure into the planar body is mixed with the main resin of theplastic bottle container, and the resultant mixture is then formed intoa preform by a usual method, e.g., injection molding.

A length of the fibrous structure and a size of the planer body aresuitably adjusted in accordance with a manufacture process of thecontainer.

The preform containing the fibrous structure or the article obtained byprocessing the fibrous structure into the planar body is subjected to,e.g., stretch blow molding, whereby the decorated plastic bottlecontainer can be obtained.

In the present embodiment, the portions which are contained in thefibrous structure and which are different in optical characteristicsfrom the surface of the plastic bottle container are neither melted nordestroyed by heat or the like during the processing of the packagingstructure.

For the purpose, for example, the very fine fibers having the island-seastructure shown in FIG. 5(b) are used. In a case where polyethyleneterephthalate is used as the main resin of the bottle container, thesame polyethylene terephthalate as the main material is used for the seaportion, and as the resin for forming the island portions, there is useda resin having a melting point higher than that of polyethyleneterephthalate, e.g., polyethylene naphthalate, carbon nanotube or anengineering plastic such as a polyimide.

When such a fibrous structure is used, PET constituting the sea portionis melted and resultantly integrated with the main material during themixing with PET which is the main material resin, but the very finefibers constituting the island portions are not melted. Therefore, onthe surface of the container, there can be formed a configuration inwhich the portions made of the main resin and the portions made of thevery fine fibers (island portions) are periodically arranged.

Third Embodiment

In the present embodiment, a fibrous structure in which island portionsare voids, or an article obtained by processing into a planar body thefibrous structure wherein the island portions are the voids is mixedwith a main resin of a plastic bottle container, so that the voidscontained in the fibrous structure are periodically arranged on thesurface of the container to decorate the container.

The fibrous structure or the article obtained by processing the fibrousstructure into the planar body is mixed with the main resin of theplastic bottle container, and then processed into a preform by a usualmethod, e.g., injection molding.

The preform containing the fibrous structure or the article obtained byprocessing the fibrous structure into the planar body can be subjectedto, for example, stretch blow molding to obtain the decorated plasticbottle container.

In a case where polyethylene terephthalate is used as the main resin ofthe bottle container and the same polyethylene terephthalate as the mainmaterial is used for the sea portion of the fibrous structure, thefibrous structure or the article obtained by processing the fibrousstructure into the planar body is mixed with PET which is the mainmaterial resin, whereby PET constituting the sea portion is melted andresultantly integrated with PET of the main material. In consequence, onthe surface of the container, there can be formed a configuration inwhich the portions made of the main resin and the portions constitutedof the voids (island portions) are periodically arranged.

Fourth Embodiment

FIG. 7 is a drawing for explaining a fourth embodiment of the decorationmethod using a fibrous structure.

In this embodiment, an article obtained by processing the fibrousstructure into a planar body is stuck onto a packaging structure tothereby decorate the packaging structure.

In FIG. 7, a planar body 43 constituted of the fibrous structure isattached onto a body surface 41 of a plastic bottle container 40.

As the planar body, there is used an article obtained by processing thefibrous structure into nonwoven fabrics, textiles or the like, asdescribed above.

As methods for sticking the planer body 43 constituted of the fibrousstructure, there are, for example, a method in which during the moldingof a plastic bottle container, a textile constituted of the fibrousstructure is inserted into an inner wall of a mold and it is stuck ontothe surface layer of the plastic bottle container by heat at the time ofheat set, and a method in which during the molding of a preform bycompression molding, a textile constituted of the fibrous structure isinserted into the inner wall of the mold and it is stuck onto thepreform by compression pressure.

Since the plastic bottle container decorated by any method of the abovefirst to fourth embodiments does not use any colorant such as a pigmentor a dye based on chemical coloring, an amount of a chemical substanceto be used can be decreased. Therefore, such a plastic bottle containerhas a less influence on the environment.

Moreover, in a case where there is used the fibrous structure made ofthe same resin as a resin which is a main material of the packagingstructure or a resin having a high compatibility, decoloring can beeasily effected by heating and kneading (re-pelletization) duringrecycling. Therefore, the plastic bottle container is decorated whenused as a container, but it becomes colorless and transparent afterreprocessing, and hence, recycle properties of the plastic bottlecontainer are very excellent.

In contrast to the chemical coloring, a vivid color tone having deepcolor and gloss can be obtained, which is effective for differentiationof products by a decoration effect.

It is to be noted that the molded plastic bottle container may bedecorated as in the above embodiment, but the preform may be decoratedwith the fibrous structure, and then molded into the bottle containerwhich is a final product.

Moreover, the method of the above embodiment can be applied to not onlythe plastic bottle container but also other packages.

Third Invention: Packaging Structure

A packaging structure of the third invention is a package mainly made ofa resin, and it is, for example, a bottle, a cup, a pouch, or a tray.This packaging structure contains a thermoplastic resin as a mainmaterial and a coloration material which gives coloring.

The packaging structure of the present invention is colored with acoloration material which is decolored or achromatized when it receivesexternal stimulation. Therefore, the packaging structure maintains thecoloration during distribution/use thereof, but it can be decolored orachromatized after the use by the external stimulation.

In this specification, the “achromatizism” means a state that a chromadifference (a²+b²)^(1/2) based on comparison with an achromatic originis in a range of 5 or less when a standard white board (X78.42, Y81.00,Z92.32) is placed on the back of a sheet having a thickness of 0.3 mmand a Hunter Lab of the sheet is then measured by a reflection method.Here, the “achromatizism” includes all states having no color fromwhite, black and gray to colorless and transparent.

In a case where the packaging structure can be achromatized by theexternal stimulation, the packaging structure can be in a state coloredwith a chromatic color which imparts a strong image to the feeling andmentality of a human during the distribution/use of the packagingstructure. In the stage of remanufacture process after the use of thepackaging structure, the packaging structure can be in an achromaticstate which does not impart the strong image and is hardly visible.Accordingly, the coloration of reproduced products with an unnecessarychromatic color can be restrained. Furthermore, in this case, an L valueof the sheet molded using a resin obtained by the reproduction of thepackaging structure is preferably 50 or more. In consequence, even whenthe packaging structure is remanufactured together with usual colorlesspackaging structures, a blackish color is restrained, so that a colortone does not largely change and hence, higher recycle properties can beobtained.

As a resin which is a main material constituting the colorationmaterial, for example, a thermoplastic polyester can be used. As thethermoplastic polyester, there can be used an aliphatic, an alicyclic oran aromatic polyester derived from a dicarboxylic component and a diolcomponent, or a copolymer or a blend thereof. Examples of thedicarboxylic component include aromatic dicarboxylic acids such asterephthalic acid, isophthalic acid and naphthalenedicarboxylic acid;aliphatic carboxylic acids such as succinic acid, adipic acid andsebacic acid; and alicyclic dicarboxylic acids such ascyclohexanedicarboxylic acid. Examples of the diol component includealiphatic glycols such as ethylene glycol, diethylene glycol andbutanediol; alicyclic glycols such as cyclohexanedimethanol (CHDM); andaromatic diols such as bisphenols. In addition, polybasic carboxylicacid components and polyhydric alcohol components having a trivalent ora higher valent functional group can also be used. Typical examples ofthe resin which can be suitably used include polyethylene terephthalate(PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN),polycarbonates, polyarylates, isophthalic acid-copolymerized PET(PET-I), cyclohexanedimethanol (CHDM)-copolymerized PET, and polyesterscopolymerized with a soft segment constituting a polyolefin or apolyether.

Of these resins, particularly preferable examples of the plastic resinwhich is the main material constituting the coloration material of thepresent invention include polyethylene terephthalate (PET), polybutyleneterephthalate (PBT), polyethylene naphthalate (PEN), polycarbonates,polyarylates, isophthalic acid-copolymerized PET (PET-I),cyclohexanedimethanol (CHDM)-copolymerized PET, and polyesterscopolymerized with a soft segment constituting a polyolefin or apolyether. In view of the fact that these resins belong to polyesters,if the polyester resin is selected as a resin which is laminatedtogether with the coloration material, the recycle properties of thepackaging structures can be enhanced.

Moreover, a thermoplastic polyamide can be used. As the thermoplasticpolyamide, there can be used an aliphatic, an alicyclic or an aromaticpolyamide derived from a dicarboxylic component and a diamine component,a polyamide derived from an aminocarboxylic acid or a lactam thereof, ora copolymer or a blend thereof. Examples of the dicarboxylic componentinclude aliphatic carboxylic acids such as succinic acid, adipic acid,sebacic acid and decanedicarboxylic acid; and aromatic dicarboxylicacids such as terephthalic acid and isophthalic acid. Examples of thediamine component include linear and branched aliphatic diamines such as1,6-diaminehexane, 1,8-diaminoocatane and 1,10-diaminodecane; alicyclicdiamines such as bis(aminomethyl)cyclohexane andbis(4-aminocyclohexyl)methane; and aromatic diamines such asm-xylylenediamine and p-xylylenediamine. In addition, examples of theaminocarboxylic acid include aliphatic aminocarboxylic acids such asω-aminocaproic acid, ω-aminooctanoic acid and ω-aminoundecanoic acid;and aromatic aliphatic aminocarboxylic acids such asp-aminomethylbenzoic acid an p-aminophenylacetic acid. Morespecifically, 6-nylon, 6,6-nylon, 11-nylon, 12-nylon, 6,10-nylon,6,12-nylon, MXD6 (m-xylyleneadipamide) nylon and the like are suitablyused.

Furthermore, an olefin resin can also be used. Examples thereof includepolyethylenes (PE) such as low-density polyethylene (LDPE),medium-density polyethylene (MDPE), high-density polyethylene (HDPE),linear low-density polyethylene (LLDPE) and linear very low-densitypolyethylene (LVLDPE); polypropylene (PP), ethylene-propylenecopolymers, polybutene-1, ethylene-butene-1 copolymers,propylene-butene-1 copolymers, ethylene-propylene-butene-1 copolymers,ethylene-vinyl acetate copolymers, ionically crosslinked olefincopolymers (ionomers) or blends thereof. In addition, there can be usedpolyacrylonitrile, polystyrene, polymethylpentene, polyvinyl alcohol,polymethyl methacrylate, cyclic olefinic copolymers (COC), andfluorinated polymers.

In the packaging structure of the present embodiment, a coloringcomponent in which color change occurs by the external stimulation isused as a colorant.

With regard to the color change, two patterns can be considered:decoloring of the coloring component by the external stimulation, and acolor change into another chromatic color.

The coloration showing a usual chromatic color occurs due to selectiveabsorption of a light having a specific wavelength by a chemicalstructure present in a material. In the former case, the chemicalstructure of at least one coloring component constituting the colorationmaterial is changed by the external stimulation to thereby loseabsorption in a visible light region, so that the material can becompletely decolored. In consequence, the packaging structure can be ina colored state during the distribution/use thereof, and in the stage ofremanufacture after use, the packaging structure can be completelydecolored, which leads to the improvement of recycle properties. Inparticular, this case is beneficial for the recycle of designated PETbottles in the second class.

In the latter case, the chemical structure of at least one coloringcomponent constituting the coloration material is changed by theexternal stimulation to reduce selectivity of a light-absorbingwavelength in a visible light region, whereby achromatization can bemade. For example, in the coloring component where a chromatic color Ais changed to B by the external stimulation, a coloring component Cwhich is a complimentary color of B can coexist. In consequence, achromatic color is appeared owing to a mixed color of A and C before theapplication of the stimulation, but the achromatization can be madeowing to a mixed color of B and C which are in relation to acomplimentary color after the application of the stimulation. Therefore,the packaging structure can be in a state colored with a chromatic colorwhich imparts a strong image to the feeling and mentality of a humanduring the distribution/use of the packaging structure. In the stage ofremanufacture process after the use of the packaging structure, thepackaging structure can be in an achromatic state which does not impartthe strong image and is hardly visible. Accordingly, the coloration ofreproduced products with an unnecessary chromatic color can berestrained. This method is effective for the recycle in use applicationswhich do not require high transparency as in the case of the designatedPET bottles in the second class.

Moreover, the external stimulation referred to here includes, forexample, physical and chemical stimulations such as heat applied duringthe reproduction of the packaging structure, light, electricity,pressure, and an environmental change around the coloring component byvarious processes. However, a stimulation that the packaging structurereceives during the distribution/use thereof is not included.

The heat which is the external stimulation includes, for example,heating for melt kneading during the reproduction of the packagingstructure, and frictional heat in a crushing step.

As mentioned above, when heating for melt kneading during thereproduction is utilized, additional facilities for decoloring orachromatizing the packaging structure are not necessary, andconveniently, an energy efficiency for the reproduction is alsoimproved.

As the coloring component in this case, there is used the coloringcomponent in which color change does not occur by heat received duringthe manufacture, distribution and use of the packaging structure, forexample, heat applied during the processing of the packaging structure,heat at the time of filling of contents, or heating, cooling or the likeduring the distribution.

As such a coloring component, for example, a thermochromic material canbe used. The thermochromic material includes an irreversible type inwhich the color change occurs by a fluctuation of a temperature but anycolor change does not occur any more by a subsequent fluctuation, and anreversible type in which the color change repeatedly occurs by thefluctuations of the temperature. In the present invention, the use ofthe former is preferred. However, even the reversible type becomesusable by suitable setting of a color change temperature or by adjustinga developer. Typical coloring components include inorganic compoundssuch as metal salts and metal complex compounds. These coloringcomponents include compounds in which chlorine, bromine, iodine, nitricacid, phosphoric acid, oxalic acid, ammonia, an amine, water or anionized compound thereof is coordinated as a ligand to a metalliccomponent of cobalt, nickel, iron, copper, molybdenum, aluminum or thelike.

Moreover, the coloring component can be obtained by a combination of aleuco dyestuff and a developer. They develop a color owing to theirinteraction, and a color change temperature can be adjusted by selectinga combination of melting points of both the substances. Furthermore, thecolor change temperature can also be adjusted by adding a thirdcomponent which affects the interaction. For example, when a resin isused as the third component, the color change temperature can be set toa desired value by selecting physical properties such as the meltingpoint of the resin. As the leuco dyestuff, there can be mentionedtriphenylmethane-based, fluorane-based, phenothiazine-based,indolylphthalide-based, spiropyran-based, rhodamine lactam-based,azaphthalide-based dyestuffs and the like. More specifically, there canbe mentioned, as triphenylmethane-based dyestuffs,3,3-bis-(p-dimethylaminophenyl)phthalide,3,3-bis-(p-dimethylaminophenyl)-6-dimethylaminophthalide,3,3-bis-(p-dimethylaminophenyl)-6-diethylaminophthalide,3,3-bis-(p-dimethylaminophenyl)-6-methoxyphthalide,4-hydroxy-4′-dimethyl-aminotriphenylmethane lactone,4-4′-bishydroxy-3,3′-bisaminotriphenylmethane lactone and the like.

Furthermore, as the developer, an organic acidic substance, an inorganicsolid acid or the like is used. The organic acidic substance includesphenols, organic acids and salts thereof. More specifically, there canbe mentioned bisphenol A, 4,4′-isopropylidnediphenol,4,4′-methylene-bis(2,6-di-tert-butylphenol), nonylphenol, dodecylphenol,α-naphthol, β-naphthol, methyl p-oxybenzoate, catechol,1-oxy-2-naphthoic acid, salicylic acid, tannic acid, methyl gallate,propyl gallate, octyl gallate and the like. These phenols and organicacids can also be used in the form of salts.

Moreover, as the inorganic solid acid, acid clay, montmorillonite,silica, silica-alumina, zinc silicate and the like are used.

In addition, the coloring component whose color is faded by heating at acertain or more temperature can also be used.

Examples of the external stimulation of the light include theirradiation of any of UV, visible lights to infrared lights, and thelike.

As the coloring component in this case, there is used the coloringcomponent in which the color change does not occur by the light receivedduring the distribution/use of the packaging structure. As such acoloring component, a photochromic material can be used. Morespecifically, organic dyestuffs such as spiropyrans, spirooxazines,fulgides, diarylethenes and azobenzenes can be mentioned. Some of thephotochromic materials bring about a structural change by heat, and thisstimulation can be used together. Moreover, as a usable irradiatinglight, the sunlight or an artificial light source can be used, and forcontrolling it, a UV absorbent, a colorant or the like may be mixed withthe coloring component, or a light-adjusting layer containing thematerial can be additionally provided. Furthermore, a stabilizer or thelike for stabilizing a structure formed with the color change can beadded.

Examples of a method for changing the color of the coloring component bythe external light include the following techniques.

The packaging structure mixed with the above coloring component isirradiated with a light such as a UV ray to change the structure of thecoloring component, thereby developing a color. In this state, thedistribution/use of the packaging structure is carried out. On the otherhand, after the use of the packaging structure, the structure of thecoloring component is changed again to give rise to the color change byheating in the melting step of the reproduction or by irradiation with alight having a wavelength different from that at the time of thecoloration.

As the electric stimulation, there is the application of a voltage orthe like. It is suitable to apply the voltage during the reproduction.

As the coloring component, there can be used substances whose colorchanges by electrochemical oxidation or reduction, e.g., electrochromicmaterials. More specifically, there can be mentioned inorganicsubstances such as tungsten oxide, iridium oxide and prussian blue,viologen compounds, phthalocyanine metal complexes, and the like. Inaddition, a stabilizer or the like for stabilizing the structure formedwith the color change can be added.

As the pressure stimulation, there are pressure which is applied in themelt kneading step of the reproduction, strain stress which remains in amolded article during the formation of the molded article, and the like.

As the coloring component whose color changes by the pressure, forexample, a piezochromic material can be used.

In addition, as the external stimulation, chemical stimulation can beused. Particularly, there can be used the coloring component whose colorchanges by change in a surrounding environment of the coloringcomponent, e.g., change in a hydrogen ion concentration, change in aconcentration of ligand of a colorant, change in a concentration of adeveloper, a polarity change induced by change in a surrounding resin,or the like.

There can be used a compound whose color changes by altering absorptioncharacteristics of a light induced due to change in chemical structureof the colorant component by changing the hydrogen ion concentration.

For example, there can be used a compound wherein coloration is achievedby combination of a hydrogen ion in a state of a high hydrogen ionconcentration, i.e., in a state of a low hydrogen ion exponent (pH) butthe color changes due to elimination of the hydrogen ion in a state ofhigh hydrogen ion exponent (pH), such as in a neutral region or in analkaline state.

As such a coloring component, for example, a halochromic material (pHindicator) can be used. More specifically, there can be used pHindicators which are already known and used, such as thymol blue, methylyellow, methyl orange, ethyl orange, methyl red, phenol red, cyanine,naphtholphtalein, cresol red, phenolphthalein and thymolphthalein. Inaddition, the aforementioned leuco dyestuffs can also be used.

As a typical method for using the above compounds, for example, in amultilayer packaging structure, an acid component is added to a layercontaining the coloring component so that the vicinity of the coloringcomponent may become an acidic atmosphere (low pH state), whereby thepackaging structure can be colored. As the acid component, for example,an organic acidic substance, an inorganic solid acid or the like isused. As the organic acidic substance, there can be mentioned phenols,organic acids and salts thereof. More specifically, there can bementioned bisphenol A, 4,4′-isopropylidnediphenol,4,4′-methylene-bis(2,6-di-tert-butylphenol), nonylphenol, dodecylphenol,α-naphthol, β-naphthol, methyl p-oxybenzoate, catechol,1-oxy-2-naphthoic acid, salicylic acid, tannic acid, methyl gallate,propyl gallate, octyl gallate and the like. These phenols or organicacids can also be used in the form of salts.

Moreover, as the inorganic solid acid, acid clay, montmorillonite,silica, silica-alumina, zinc silicate, and the like can be mentioned.

As in the above, since the vicinity of the coloring component ismaintained under an acidic atmosphere during the distribution/use of thepackaging structure, it can be in a colored state.

On the other hand, at the remanufacture process after use, it can bedecolored or achromatized by the dilution step where it is mixed withthe other layer of the packaging structure or the other packagingstructure or the alkali washing step. Namely, the layer containing thecoloring component is mixed with the other layer of the packagingstructure or the other packaging structure in the dilution step and meltkneaded, whereby the hydrogen ion is diluted to decrease a hydrogen ionconcentration in the vicinity of the coloring component. Decoloring orachromatizing the packaging structure is effected by change in structureof the coloring component induced by the above change. Moreover, in thealkali washing step, since treatment is conducted in an environment ofpH 10 to 14, the coloring component is decolored or achromatized by thechemical stimulation.

In this connection, not the organic acid but an organic base can beused. For example, a coloring component can also be used, which iscolored by making the vicinity of the coloring component a basicatmosphere (high pH state) with an amine-based organic base such asethylenediamine, diethanolamine, triethylamine, or pyridine.

According to the same method as in the above, there can be used acoloring component whose color can be changed by changing a ligandconcentration in the vicinity of the coloring component. Namely, a layercontaining the coloring component is colored in a state that the ligandconcentration is high, and after use, the ligand concentration isdecreased in the dilution step and melt kneading step at theremanufacture process, whereby the layer can be decolored orachromatized.

As such a coloring component, there can be, for example, mentionedinorganic compounds such as metal salts and metal complex compounds. Asthese compounds, there can be used those wherein chlorine, bromine,iodine, nitric acid, phosphoric acid, oxalic acid, ammonia, amines,water, and ionized compounds thereof are coordinated as ligands tometallic components such as cobalt, nickel, iron, copper, molybdenum,and aluminum. Color change occurs when an equilibrium state is broken bythe occurrence of change in the surrounding ligand concentration and acomplex is again formed along with transition to a new equilibriumstate.

Moreover, similarly, there can be used a coloring component whose colorchanges by changing a concentration of a developer.

As such a combination of the color component, a combination of a leucodyestuff and a developer can be used. They develop color by theirinteraction and color change can also be controlled by adding a thirdcomponent (decoloring material) which inhibits the interaction. As theleuco dyestuff, there can be mentioned triphenylmethane-based,fluorane-based, phenothiazine-based, indolylphthalide-based,spiropyran-based, rhodamine lactam-based, azaphthalide-based dyestuffs,and the like. More specifically, there can be mentioned astriphenylmethane-based dyestuffs,3,3-bis-(p-dimethylaminophenyl)phthalide,3,3-bis-(p-dimethylaminophenyl)-6-dimethylaminophthalide,3,3-bis-(p-dimethylaminophenyl)-6-diethylaminophthalide,3,3-bis-(p-dimethylaminophenyl)-6-methoxyphthalide,4-hydroxy-4′-dimethyl-aminotriphenylmethane lactone,4-4′-bishydroxy-3,3′-bisaminotriphenylmethane lactone, and the like.

Furthermore, as the developer, an organic acidic substance, an inorganicsolid acid, or the like is mentioned. More specifically, bisphenol A,4,4′-isopropylidnediphenol, 4,4′-methylene-bis(2,6-di-tert-butylphenol),nonylphenol, dodecylphenol, α-naphthol, β-naphthol, methylp-oxybenzoate, catechol, 1-oxy-2-naphthoic acid, salicylic acid, tannicacid, methyl gallate, propyl gallate, octyl gallate, and the like. Thesephenols or organic acids can also be used in the form of salts.

Moreover, as the inorganic solid acid, acid clay, montmorillonite,silica, silica-alumina, zinc silicate, and the like are used.

Furthermore, there can be used a coloring component whose color changesby change in polarity (hydrogen bond-donating ability) by changingsurrounding resin of the coloring component. For example, there can beused a coloring component wherein coloring component is colored whenadded to a resin layer of a gas barrier layer of the packaging structureand color change is effected by changing the resin in the vicinity ofthe coloring component by melt kneading with the other resin at therecycling.

As such a coloring component, a solvatochromic dyestuff can be used. Asolvatochromic dyestuff has a structure containing an electron-acceptorgroup and an electron-donor group at both ends of a π-conjugated systemconstituted of two or more carbon atoms, respectively. Therefore,polarizability of the conjugated system is high and hence color changeoccurs by the influence of the environment, such as change insurrounding polarity. More specifically, organic dyestuffs such asbetains, melocyanines, spiropyrans, and spirooxazines can be used.

In addition, a halochromic material (pH indicator) can be used. Ahalochromic material is generally known as a material whose colorchanges by desorption of a hydrogen ion but similar color change occursby interaction with a hydrogen bond-donating group such as hydroxylgroup which determines polarity of a substance. More specifically, theaforementioned pH indicators and leuco dyestuffs can be used. A pHindicator has an inherent acid dissociation constant (Ka) and the valuedetermines a pH region of color change. In a case where change inpolarity is used as environmental change in the vicinity of the coloringcomponent, it is necessary to select a pH indicator having a suitableacid dissociation constant so that the polarity region before and afterthe change in polarity becomes the region of color change.

In the coloration wherein a conventional colorant such as a pigment or adye is used, the coloration is only paled in accordance with theLambert-Beer rule even when diluted in the dilution step. However, byusing the above coloring component, the coloring component itself ischanged to effect color change in the packaging structure of the presentinvention, it becomes possible to achieve decoloration at a highefficiency without following the above rule.

Into the coloring component, known resin additives such as a filler, acolorant, a heat-resistant stabilizer, a light-resistant stabilizer, anantioxidant, an antiaging agent, a light stabilizer, a UV absorber, anantistatic agent, a lubricant such as a metal soap or wax, and amodifying resin or rubber can be mixed according to formulation knownper se. For example, by mixing a lubricant, it is possible to reduce aload to the coloring component induced by shearing at melt processingand improve inroad of a resin into the screw of an extruder.

The packaging structure may have a single-layer structure containing theabove resin as a base material or may have a multilayer structurecontaining two or more layers. Since a surrounding environment of thecoloring component of the packaging structure can be easily changed inthe remanufacture during the distribution/use of the packaging structureand after use, it is preferred to be a laminate structure constituted ofa layer containing the coloring component and the other layer(s). Thisis because use of the laminate structure constituted of a layercontaining the coloring component and the other layer(s) causesenvironmental change in the vicinity of the coloring component throughdilution of the coloring component with the other layer(s) induced bymelt kneading in the remanufacture process, the environmental changebeing able to utilize as external stimulation.

The resin layer other than the coloration material layer constitutingthe packaging structure can be suitably selected from thermoplasticresins and thermosetting resins depending on the uses and requiredfunctions.

As the resins to be selected in this case, there can be, for example,mentioned olefin resins, thermoplastic polyester resins, and the like.

Examples of the olefin resins include low-density polyethylene (LDPE),medium-density polyethylene (MDPE), high-density polyethylene (HDPE),linear low-density polyethylene (LLDPE), linear very low-densitypolyethylene (LVLDPE), polypropylene (PP), ethylene-propylenecopolymers, polybutene-1, ethylene-butene-1 copolymers,propylene-butene-1 copolymers, ethylene-propylene-butene-1 copolymers,ethylene-vinyl acetate copolymers, ionically crosslinked olefincopolymers (ionomers), and blends thereof.

Moreover, examples of the thermoplastic polyester resins includepolyethylene terephthalate (PET), polybutylene terephthalate (PBT),polyethylene naphthalate (PEN), polycarbonates, polyarylates,isophthalic acid-copolymerized PET (PET-I), cyclohexanedimethanol(CHDM)-copolymerized PET, and polyesters copolymerized with a softsegment constituting a polyolefin or a polyether.

However, the resin layer other than the coloration layer constitutingthe packaging structure is, in particular, preferably a layer made of apolyester resin. When the resin layer other than the coloration layer isa layer constituted of a polyester layer, the recycle properties of thepackaging structure can be enhanced by using a polyester-based resin asthe main material of the coloration material.

Furthermore, the packaging structure may contain various layers in orderto impart required function(s). For example, the packaging structure mayhave a gas barrier layer. Examples of the barrier resins includeethylene-vinyl alcohol copolymers (EVOH), cyclic olefinic copolymers(COC), especially copolymers of ethylene with cyclic olefins (APELmanufactured by Mitsui Chemicals, Inc., etc.), and m-xylyleneadipamide(MXD6).

In addition, an adhesive resin can also be interposed between therespective resin layers, if necessary. As such an adhesive resin, therecan be mentioned thermoplastic resins having carbonyl groups based on acarboxylic acid, a carboxylic anhydride, a carboxylate salt, acarbamide, a carboxylate ester in main chains or side chains. Suitableexamples of the adhesive resin include one or a combination of two ormore of ethylene-acrylic acid copolymers, ionically crosslinked olefincopolymers, maleic anhydride-grafted polyethylene, maleicanhydride-grafted polypropylene, acrylic acid-grafted polyolefins,ethylene-vinyl acetate copolymers, copolymerized polyesters,copolymerized polyamides, and the like. The coloration layer may possessboth functions of coloration and barrier ability.

The packaging structure of the present invention can be manufactured bya known method except that the above coloring component is used.

For example, the processing of films, sheets, or tubes can be conductedby mixing a coloring component with a base resin by dry blend or meltblend, melt kneading them in an extruder, and subsequently extrudingresins into a predetermined form through a T-die, a circular die (ringdie), or the like to obtain T-die films, brown films, or the like. TheT-die film is biaxially stretched to form a biaxially stretched film.

Moreover, a coloring component is mixed with a base resin and the wholeis melt kneaded in an extruder and then extruded into a certain meltresin mass, which is subjected to compression molding to produce acontainer or a preform for manufacturing containers.

The molded article may be in a form of a pariosn for forming films,sheets, bottles or tubes or a preform for forming pipes, bottles, andtubes.

The bottle molding from a parison, pipe or preform can be easilyconducted by pinching off the extruded product with one pair of splitmold and blowing a fluid into the inside.

Moreover, after a pipe or preform is cooled, it is heated to stretchtemperature and then stretched in the axial direction and simultaneouslyblow-stretched in the circumferential direction by fluid pressure,whereby stretched blow bottles can be molded.

Furthermore, by subjecting a film or a sheet to means such as vacuumforming, pneumatic forming, bulging, or plug-assist forming, packagingcontainers of cup-shape, tray-shape, or the like shape or cappingmembers are obtained.

The packaging materials such as films can be used as various forms ofpackaging bags. The bag manufacture can be conducted bybag-manufacturing methods known per se and there can be mentioned usualthree-sided or four-sided seal pouches, pouches with gazette, standingpouches, pillow packaging bags, and the like

For manufacturing a multilayer extrusion molded article, co-extrusionmolding or multilayer injection molding known per se can be utilized.For example, using extruders whose number corresponds to the kinds ofresins, extrusion molding may be conducted in the same manner as in theabove except that a multiple multilayer die is used.

Moreover, for manufacturing a multilayer injection molded article, by asimultaneous injection method or sequential injection method, amultilayer injection molded article can be manufactured using extruderswhose number corresponds to the kinds of resins.

Furthermore, for manufacturing a multilayer compression molded article,using extruders whose number corresponds to the kinds of resins, amultilayer compression molded article can be manufactured by extrudingthe resins as a certain resin mass through a multiple multilayer die andsubjecting it to compression molding with a mold.

In addition, for manufacturing a multilayer film or a multilayer sheet,a multilayer film or sheet can be obtained by an extrusion-coatingmethod, a sandwich lamination method, or dry lamination of pre-processedfilms.

Moreover, the packaging structure of the present invention can beobtained by coating a packaging structure with a coating materialcontaining a coloring component.

In the coating, lamination can be effected by preparing a coatingmaterial by dispersing a coloring component in a base material havingcurability using additives such as a solvent and a dispersant accordingto needs, applying the coating material on the other resin layer surfaceby a known method such as gravure coating, spray coating, or dipcoating, and curing into a cured coated film by heat or a method of UVirradiation or the like.

For example, in a case where a coloring component which is colored byirradiation with a light is used in the packaging structure manufacturedby the above method or that a coloring component which is colored byelectric stimulation is used therein, coloring is conducted according toneeds.

Since the packaging structure of the present invention manufactured bythe above method uses a coloring component whose color changes byexternal stimulation, the structure can be easily decolored or convertedinto an achromatic color by applying a specific external stimulation atthe remanufacture process after use.

When the reproduced resin obtained by remanufacture at this time ismolded into a sheet having a thickness of 0.3 mm and Hunter Lab of thesheet is measured with placing a standard white board (X78.42, Y81.00,Z92.32) on the back of the sheet by the reflection method, a chromadifference (a²+b²)^(1/2) from an achromatic origin is preferably 5 orless. When the chroma difference of the reproduced resin is 5 or less,it is evaluated as achromatic in appearance and the coloration ofreproduced products with unnecessary chromatic color can be restrained.

Fourth Invention: Reproduction Method

A method of reproduction of the present invention comprises collectingthe packaging structure and melting it to effect reproduction, whereinthe melting for the reproduction is conducted at a temperature equal toor higher than the temperature at which the coloring component containedin the packaging structure is decolored.

The melting can be conducted, for example, using a melt-extruder or thelike.

In the reproduction process, steps necessary for manufacturingreproduced products, such as washing and separation are included inaddition to the melting.

The melting for the reproduction is conducted at a temperature equal toor higher than the temperature at which the coloring component containedin the packaging structure is decolored.

For example, in a case where the temperature at which the coloringcomponent is decolored is 220° C., the melting temperature is set to atemperature equal to or higher than 220° C. (e.g., 250° C.). Morespecifically, for example in a case where the melting of a resin isconducted in a melt-extruder, the set temperature of a flow path throughwhich the resin is carried in a melted state is set to 250° C. or thelike.

By conducting the melting at such a temperature, the packaging structureis decolored due to destruction of the regular configuration of thecoloring component contained. Thereby, even when the packaging structurecollected has been colored, the color can be removed at the meltingstage.

Namely, the packaging structure of the present invention can possessfunctions of a visible light barrier and a decoration by coloration inthe production process. On the other hand, in thecollection/remanufacture process, the packaging structure can satisfythe reuse suitability evaluation through decoloring and thus becomesrecyclable. Therefore, a reuse ratio of the containers and the likemolded with the packaging structure is enhanced and hence recycling canbe promoted.

Measurement of Decoloring Temperature of Coloring Component

Melting points of the constituting polymers were measured on, e.g.,Morphotex (registered trademark) finely crushed product (crush length150 μm) [made by Teijin Fibers Ltd.] having a multiple multilayerstructure of two resins polyethylene terephthalate (PET) and nylon(Ny-6)) different in refractive index by differential scanningcalorimetry and were found to be 220° C. and 250° C. Moreover, when thematerial was heated at 10° C./min with observing appearance through anoptical microscope on a hot stage, it was decolored at 220° C.

From these results, the decoloring temperature of Morphotex was 220° C.,which corresponds to the melting point of Ny-6 as a constitutingpolymer.

Moreover, as another embodiment of the reproduction method, there is amethod of reproduction of the above packaging structure, wherein thepackaging structure is decolored or achromatized by applying externalstimulation in at least one step of a melting step, a dilution step andan alkali-washing step at reproduction of the packaging structure.

In these steps, external stimulation is applied to the packagingstructure to decolor or achromatize the packaging structure, whereby arestriction on color tone for the remanufacture of the colored moldedarticles is relieved and hence productivity can be enhanced.

Moreover, by decoloring induced by stimulation in the dilution step, thealkali washing step, and the melt kneading step for the reproduction,the colored packaging structure can be remanufactured without newfacilities.

EXAMPLES Resin Composition Example 1

Metallocene PE (KS560T) [Japan Polychem Corporation] (99.5 wt %) as amatrix resin was mixed with 0.5 wt % (dry blend) of a finely crushedproduct (crush length 150 μm) of Morphotex (registered trademark) [madeby Teijin Fibers Ltd.] as a colorant component, followed by pre-kneadingin a stirring drying machine [made by Dalton Co., Ltd.]. Afterward, aninjection molding machine (NN75S) [made by Niigata Ironwork Co., Ltd.]was used at a plasticizing temperature of 200° C. to prepare a sheethaving a thickness of 1.5 mm. At this time, the molded sheet wascolored. The thus prepared sheet was enlargedly observed through anoptical microscope, so that it was confirmed that Morphotex was notdestroyed.

Comparative Example 1

The same procedure as in Example 1 was carried out except that theplasticizing temperature of the injection molding machine was 270° C.,to prepare a sheet having a thickness of 1.5 mm. At this time, themolded sheet was decolored. The thus prepared sheet was enlargedlyobserved through an optical microscope, so that it was found thatMorphotex was destroyed and its presence could not be confirmed.

Packaging Structure Example 2

95 wt % of Metallocene PE as a matrix resin was mixed with 5 wt % of afinely crushed product of Morphotex to prepare masterbatch pellets, andthe thus prepared pellets were then processed using a twin screwextruder equipped with a powder-feeding device, a cooling conveyer and apelletizer.

Afterward, in a co-injection molding machine, polyethylene terephthalate(RT543CTHP) [Japan Unipet Co., Ltd.] was fed to injection machines foran inner layer and an outer layer (set temperature 280° C.). Thepreviously processed masterbatch pellets were fed to an injectionmachine for an intermediate layer and then co-injection molded into aninjection mold to obtain a two-kind three-layer preform (32 g)containing the inner and outer layers of polyethylene terephthalate andthe intermediate layer containing 25 wt % of a colorant layer.Afterward, this preform was subjected to biaxial stretch blowing to molda two-kind three-layer multilayer bottle having a content of 500 ml.

In the co-injection molding, a set temperature of the injection machinefor the intermediate layer and a temperature of a hot runner for theintermediate layer were set to 200° C. which was lower than a decoloringtemperature of Morphotex (220° C.). As a result, the multilayer bottleobtained by the biaxial stretch blowing was colored.

Comparative Example 2

The same procedure as in Example 2 was carried out except that the settemperature of the injection machine for the intermediate layer and thetemperature of the hot runner for the intermediate layer in theco-extrusion molding were set to 270° C. which was higher than thedecoloring temperature of Morphotex (220° C.), to form a two-kindthree-layer multilayer bottle. At this time, the multilayer bottleobtained by the biaxial stretch blowing was not colored.

Example 3

95 wt % of CHDM copolymerized PET (IV=0.65) as a matrix resin was mixedwith 5 wt % of a finely crushed product of Morphotex to preparemasterbatch pellets, and the thus prepared masterbatch pellets were thenprocessed using a twin screw extruder equipped with a powder-feedingdevice, a cooling conveyer and a pelletizer.

Afterward, in a co-injection molding machine, polyethylene terephthalate(RT543CTHP) [Japan Unipet Co., Ltd.] was fed to injection machines foran inner layer and an outer layer (set temperature 280° C.). Thepreviously processed masterbatch pellets were fed to an injectionmachine for an intermediate layer and then co-injection molded into aninjection mold to obtain a two-kind three-layer preform (32 g)containing the inner and outer layers of polyethylene terephthalate andthe intermediate layer containing 25 wt % of a colorant layer.Afterward, this preform was subjected to biaxial stretch blowing to molda two-kind three-layer multilayer bottle having a content of 500 ml.

In the co-injection molding, a set temperature of the injection machinefor the intermediate layer and a temperature of a hot runner for theintermediate layer were set to 200° C. which was lower than a decoloringtemperature of Morphotex (220° C.). As a result, the multilayer bottleobtained by the biaxial stretch blowing was colored.

Comparative Example 3

The same procedure as in Example 3 was carried out except that the settemperature of the injection machine for the intermediate layer and thetemperature of the hot runner for the intermediate layer in theco-injection molding were set to 270° C. which was higher than thedecoloring temperature of Morphotex (220° C.), to mold a two-kindthree-layer multilayer bottle. At this time, the multilayer bottleobtained by the biaxial stretch blowing was not colored.

Example 4 Preparation of Coloration Material Pellets

Crystal violet lactone [made by Kishida Chemical Co., Ltd.] (0.2 wt %)as a leuco dyestuff and propyl gallate [made by Kishida Chemical Co.,Ltd.] (0.1 wt %) as a developer were allowed to adhere to pellets ofMetallocene PE (KS560T) [made by Japan Polychem Corporation] (99.7 wt %)by dry blending, to prepare coloration material pellets.

Preparation of Decoloration Material Pellets

Methyl cholate [made by Kishida Chemical Co., Ltd.] (0.1 wt %) as adecoloring component was allowed to adhere to pellets of Metallocene PE(KS560T) [made by Japan Polychem Corporation] (99.9 wt %) by dryblending, to prepare decoloration material pellets.

Processing of Multilayer Sheet

The coloration material pellets and the decoloration material pelletswere fed to two extruders each equipped with a two-layer T-die(Laboplasto mill) [made by Toyo Seiki Co., Ltd.], respectively, to molda two-layer sheet having a total thickness of 0.3 mm (colorationmaterial layer/decoloration material layer 0.15 mm/0.15 mm). All settemperatures of a plasticizing device, paths and the die were 150° C.The molded sheet was colored dark blue (Sample 1-a). Afterward, a colortone of the obtained sheet was measured.

For the decoloration of this sheet, the sheet was cut into a size of 5×5mm and then fed to a material hopper of an injection molding machine(NN75S) [made by Niigata Ironwork Co., Ltd.], and a plasticizingtemperature was set to 150° C. to prepare a sheet having a thickness of1.5 mm. At this time, the molded sheet was substantially colorless andtransparent (Sample 1-b). Afterward, the obtained sheet was regulated soas to be a thickness of 0.3 mm by thermal compression at 120° C., andthen a color tone was measured.

The color tone of the sheet was measured by placing a standard whiteboard (X78.42, Y81.00, Z92.32) on the back of the sheet having athickness of 0.3 mm, and then measuring a Hunter Lab of the sheet by areflection method in a color computer (SM-4) [Suga Test Instruments Co.,Ltd.].

Comparative Example 4

The same procedure as in Example 4 was carried out except that insteadof the decoloration material pellets, PE virgin pellets were fed to theextruder equipped with a two-layer T-die to mold a sheet having a totalthickness of 0.3 mm (coloration material layer/decoloration materiallayer=0.15 mm/0.15 mm). The molded sheet was colored dark blue (Sample1′-a).

For the decoloration of this sheet, the sheet was cut into a size of 5×5mm and then fed to a material hopper of an injection molding machine(NN75S) [made by Niigata Ironwork Co., Ltd.], and a plasticizingtemperature was set to 150° C. to prepare a sheet having a thickness of1.5 mm. At this time, the molded sheet was colored blue (Sample 1′-b).Afterward, the obtained sheet was regulated so as to be a thickness of0.3 mm by thermal compression at 120° C., and then a color tone wasmeasured.

Example 5

A copolymerized polyester (Vylon GM990) [made by Toyobo Co., Ltd.](97.99 wt %) was mixed with potassium cobalt phosphate [made by TeradaChemishe Fabrik] (2 wt %) which was a heat-fading pigment and a yellowpigment (GRAPHTOL YELLOW H2R) [made by Clariant Japan] (0.01 wt %) ascoloring components to prepare masterbatch pellets, and the thusprepared pellets were then processed using a twin screw extruderequipped with a powder-feeding device, a cooling conveyer and apelletizer.

Afterward, in a co-injection molding machine, polyethylene terephthalate(RT543CTHP) [Japan Unipet Co., Ltd.] was fed to injection machines foran inner layer and an outer layer (set temperature 280° C.). Thepreviously processed masterbatch pellets were fed to an injectionmachine for an intermediate layer (set temperature 150° C.) and thenco-injection molded into an injection mold to obtain a two-kindthree-layer preform (32 g) containing the inner and outer layers ofpolyethylene terephthalate and the intermediate layer containing 25 wt %of a colorant layer. Afterward, this preform was subjected to biaxialstretch blowing to mold a two-kind three-layer multilayer bottle havinga content of 500 ml. The molded bottle was colored orange which was achromatic color (Sample 2-a). A color tone of a body portion (thickness0.3 mm) of the obtained bottle was measured.

For the decoloration of this bottle, the bottle was crushed into flakesin a crusher (VC3-360) [made by Horai Co., Ltd.], and the flakes werefed to an extruder equipped with a T-die (Laboplasto mill) [made by ToyoSeiki Co., Ltd.] to mold a sheet having a total thickness of 0.3 mm. Allset temperatures of a plasticizing device, paths and the die were 280°C. The molded sheet showed gray which was an achromatic color (Sample2-b). Moreover, a color tone of the resulting sheet was measured.

Comparative Example 5

The same procedure as in Example 5 was carried out except that potassiumcobalt phosphate was removed, to mold a two-kind three-layer multilayerbottle having a content of 500 ml. The molded bottle was colored yellowwhich was a chromatic color (Sample 2′-a). A color tone of a bodyportion (thickness 0.3 mm) of the obtained bottle was measured.

Similarly, for the decoloration of this bottle, the bottle was crushedinto flakes in a crusher (VC3-360) [made by Horai Co., Ltd.], and theflakes were then fed to an extruder equipped with a T-die (Laboplastomill) [made by Toyo Seiki Co., Ltd.] to mold a sheet having a totalthickness of 0.3 mm. All set temperatures of a plasticizing device,paths and the die were 280° C. The molded sheet showed yellow which wasa chromatic color (Sample 2′-b). Moreover, a color tone of the obtainedsheet was measured.

The results of the above measurements are shown in Table 1. TABLE 1Color Tones of the Molded Sheets Decolora- tion Sample L a b (a² +b²)^(1/2) Appearance Example 4 Before  1-a 81.94 −2.73 −7.84 8.30 BlueAfter  1-b 82.03 −2.53 −1.37 2.88 Colorless transparent Comp. Before1′-a 81.94 −2.73 −7.84 8.30 Blue Example 4 After 1′-b 83.82 −2.65 −5.285.91 Blue Example 5 Before  2-a 81.16 1.50 13.00 13.09 Orange After  2-b78.22 2.00 4.50 4.92 Gray Comp. Before 2′-a 84.17 −2.61 17.09 17.29Yellow Example 5 After 2′-b 82.54 −2.14 18.23 18.36 Yellow

INDUSTRIAL APPLICABILITY

According to the present invention, a coloring component constituted ofa polymer and having a regular configuration as a coloring principle iscontained in a matrix resin, and therefore, a resin composition(packaging structure) can be colored by its physical coloring mechanism.

Furthermore, since a temperature at which the coloring component isdecolored is higher than a processing temperature of the matrix resin,the resin composition (packaging structure) can be colored by setting aset temperature for injection molding at the processing temperature ofthe matrix resin. Moreover, the resin composition (packaging structure)can be decolored by setting a set temperature of melt extrusion to atemperature higher than a temperature at which the coloring component isdecolored.

Therefore, the resin composition (packaging structure) can be colored byinjection molding in a manufacture process in a flow ofmanufacture/recycling, and the resin-composition (packaging structure)can be decolored by melt extrusion in a collection/remanufactureprocess.

Consequently, in a distribution process, functions of a visible lightbarrier and a decoration by coloration of the resin composition(packaging structure) can be exerted, and it is decolored in thecollection/remanufacture process, whereby the recycle of the packagingstructure is possible.

Accordingly, a reuse ratio of containers (e.g., PET bottles) molded fromthe resin composition (packaging structure) can be enhanced, which canpromote the recycle of the packaging structure.

Moreover, according to the present invention, a packaging structure anda decoration method thereof can be provided in which the decoration canbe achieved by a physical coloring mechanism, and even when decorated,the recycle of the packaging structure is easy.

Furthermore, according to the present invention, a packaging structurecan be provided in which when a package is colored by use of a coloringcomponent whose configuration changes by external stimulation to bringabout color change, the packaging structure is colored during thedistribution/use, but after use, the packaging structure can be easilydecolored or achromatized by the external stimulation in a processingstep or the like during the recycle.

1. A resin composition wherein a coloring component comprising a polymerand having a regular configuration as a coloring principle is containedin a matrix resin, and a temperature at which the coloring component isdecolored is higher than a processing temperature of the matrix resin.2. The resin composition according to claim 1, wherein when the coloringcomponent comprises a plurality of polymers, a melting pointcorresponding to the temperature at which one of the plurality ofpolymers is decolored is higher than the processing temperature of thematrix resin.
 3. The resin composition according to claim 1, wherein thecoloring component is a multilayer laminate of two or more resins whoserefractive indices are different from each other.
 4. A packagingstructure using the resin composition according to claim
 1. 5. Thepackaging structure according to claim 4, which has one or more layerscomprising the resin composition and one or more layers comprising apolyester.
 6. The packaging structure according to claim 4, wherein thematrix resin constituting the resin composition is a polyester.
 7. Thepackaging structure according to claim 4, wherein at least one polymerof the one or more polymers constituting the coloring component is apolyester.
 8. The packaging structure according to claim 4, wherein theresin composition is laminated by co-extrusion.
 9. The packagingstructure according to claim 4, wherein the resin composition islaminated by coating.
 10. A packaging structure wherein, on at least aportion of the surface of the packaging structure, portions which aredifferent in optical characteristics from the surface are periodicallyarranged by use of a fibrous structure.
 11. The packaging structureaccording to claim 10, wherein the portions which are different inoptical characteristics are portions different in refractive index fromthe surface of the packaging structure.
 12. The packaging structureaccording to claim 10, wherein the portions which are different inoptical characteristics are voids formed inside the fibrous structure.13. A method for decorating a packaging structure, wherein thedecoration is conducted by forming a configuration in which on at leasta portion of the surface of the packaging structure, portions which aredifferent in optical characteristics from the surface are periodicallyarranged by use of a fibrous structure.
 14. The method for decoratingthe packaging structure according to claim 13, wherein the decoration isconducted by winding the fibrous structure around a surface layer of thepackaging structure.
 15. The method for decorating the packagingstructure according to claim 13, wherein the decoration is conducted bymixing the fibrous structure with a resin which forms the packagingstructure.
 16. The method for decorating the packaging structureaccording to claim 13, wherein the packaging structure is decorated witha planar body formed by processing the fibrous structure.
 17. A methodfor reproducing a packaging structure, which comprises collecting thepackaging structure according to claim 4, melting and reproducing it,wherein the melting for the reproduction is conducted at a temperatureequal to or higher than a temperature at which a coloring componentcontained in the packaging structure is decolored.
 18. A method forreproducing a packaging structure, which comprises collecting thepackaging structure according to claim 5, melting and reproducing it,wherein the melting for the reproduction is conducted at a temperatureequal to or higher than a temperature at which a coloring componentcontained in the packaging structure is decolored.
 19. A packagingstructure which contains a coloration material comprising one or morecoloring components and which is decolored or achromatized by externalstimulation after use.
 20. The packaging structure according to claim19, wherein a coloring mechanism of the coloration material is due tolight absorption in a visual light region.
 21. The packaging structureaccording to claim 19, wherein the packaging structure is a laminatedstructure having a layer containing the coloration material.
 22. Thepackaging structure according to claim 19, which has one or more layerscomprising the coloration material and one or more layers comprising athermoplastic resin.
 23. The packaging structure according to claim 19,wherein the coloration material contains a resin as a main material. 24.The packaging structure according to claim 19, wherein a main materialresin of a layer comprising the coloration material is the same kind ofresin as a thermoplastic resin constituting at least one layer of otherlayers comprising a thermoplastic resin.
 25. The packaging structureaccording to claim 19, which is decolored or achromatized by changing achemical structure of at least one component constituting the colorationmaterial by external stimulation.
 26. The packaging structure accordingto claim 19, wherein the external stimulation is stimulation by heat ora light.
 27. The packaging structure according to claim 19, wherein theexternal stimulation is change in a surrounding environment of thecoloring component.
 28. The packaging structure according to claim 27,wherein the change in a surrounding environment is change in a hydrogenion concentration, change in a polarity, change in a ligandconcentration, change in a developer concentration, or change in asurrounding resin.
 29. The packaging structure according to claim 19,wherein a chroma difference (a2+b2)½ between a sheet molded using aresin obtained by reproducing the packaging structure and an achromaticorigin is 5 or less.
 30. A method for reproducing the packagingstructure according to claim 19, wherein the packaging structure isdecolored or achromatized by applying external stimulation thereto in atleast one step of a melting step, a dilution step and an alkali-washingstep during reproduction of the packaging structure.